6. Data Collection

This chapter presents the basic data collection procedures given to field staff working on the 2000 NHSDA. For further details or specific instructions, consult the 2000 NHSDA Field Interviewer Manual.

6.1 Contacting Dwelling Units

Interviewers were assigned specific sample dwelling units (SDUs) to contact with the addresses or unit/location descriptions displayed on the Newton handheld computer. The sample was released in partitions, with additional units made available as needed depending on progress during the initial weeks of data collection each quarter.

6.1.1 Lead Letter

RTI made initial contact with residents of the specific SDUs by sending a lead letter which gave a brief explanation of the nature of the study and its methods. The letter was printed on Department of Health and Human Services (DHHS) letterhead and signed by both the SAMHSA Assistant Project Officer and the RTI National Field Director.

Prepared letters preprinted with the addresses of all SDUs were included with the assignment materials distributed to FIs each quarter. Interviewers reviewed all addresses for completeness, signed the letters, and mailed them prior to and throughout the first part of the quarter so that the letters arrived fairly close to the time the FI expected to be in the area. Any SDUs lacking a complete mailing address were not sent a letter. To allow for these cases and other instances of delivery problems, each interviewer had extra copies to give to respondents during a personal visit. A copy of the letter, in both English and Spanish, was also included in the Showcard Booklet for reference.

6.1.2 Initial Approach

Before knocking on the door of an SDU, the FI selected the appropriate case for that specific unit on the Newton. Each FI possessed a personalized letter of authorization printed on DHHS letterhead authorizing the FI by name to work on the study and approached the door of the SDU with his/her RTI identification badge clearly visible. The FI also carried a variety of informational materials such as Question and Answer Brochures, NHSDA Highlights, and copies of newspaper articles about NHSDA.

6.1.3 Introduction/Statement of Confidentiality/Informed Consent

When contacting the unit, the FI asked to speak with an adult resident (18 or older) of the unit who could serve as the screening respondent. The FI introduced himself/herself and the study. As scripted on the Newton screen, during the introduction the FI mentioned the lead letter and gave the screening respondent the Statement of Confidentiality. The Statement of Confidentiality, which was also included in the Showcard Booklet for reference, explained the purpose of the data collection effort, assured the respondent that all information gathered would be handled in the strictest confidence, and estimated the time required to complete the interview. The Statement also advised respondents that there were no known risks or benefits to their participation and that respondents were free to withdraw from the study at any time. Therefore, the Statement of Confidentiality provided all required aspects of Informed Consent for both the screening and interviewing portions of the study.

6.1.4 Callbacks

If no respondent was available or another situation was found at the unit so that screening could not be completed during the first visit, a minimum of four callbacks were made to the unit so that each SDU was visited at least five times in an effort to complete the screening. These contacts were made at different hours on different days of the week to increase the likelihood of completing the screening.

6.2 Dwelling Unit Screening

Screening was performed at each SDU by obtaining information about the residents of the unit to determine whether or not any household member would be eligible for the NHSDA interview based on the ages of the SDU members. The screening program guided the FIs through the process of asking age, gender, race/ethnicity, and military status for all persons aged 12 and older who lived at the unit for most of the calendar quarter, and the information was entered into the Newton.

6.3 Within-Dwelling Unit Selection

Once the roster information was entered and verified, the FI started the within-dwelling unit selection algorithm on the Newton by tapping the "Make Selection" button. The Newton automatically determined, based on the composition of the household roster, whether or not anyone in the unit was selected for the interview.

The system allowed for the selection of none, one, or two members of a household for an interview. Dwelling units with 12- to 17-year-olds on the roster were more likely to have persons selected for an interview. It was possible that if two household members were chosen, they could be within the same age group.

In order to identify each selected individual, the Newton displayed the person's roster number (based on the order in which household members were listed), the age, gender, and either the relationship to the householder (for housing units) or a first name (for group quarters units). Also displayed was the mode of the interview, usually "NHSDA Interview" for a Main Study interview. (For those staff also working on the Validity Study research project, the mode may have been "Validity Interview.") Also listed on the Newton was a QuestID number, which was required to start the computerized interview on the laptop. FIs transmitted all the completed screening data contained on the Newton to RTI each evening.

6.4 Interview Administration

6.4.1 Informed Consent/Getting Started

Once the selected individual(s) were identified during screening, the FI asked to complete the interview(s) at that time. If unavailable, the FI entered information about possible times for future contacts in the Newton Record of Calls. A minimum of four additional visits were made at different times of day/days of the week in an attempt to complete the interview.

For adults selected for the CAI interview, the FI used introductory scripts from the Showcard Booklet to introduce the study and the interview process. To meet the requirements of Informed Consent, the Statement of Confidentiality was provided as well. After receiving consent, the FI set up the computer equipment in a private location and began the interview.

If the selected individual was aged 12-17, the FI was responsible for obtaining verbal consent from a parent or guardian before contacting the youth. The only exceptions to this rule were in certain group quarters situations, like dormitories, where such consent was unobtainable, or if the youth was an emancipated minor. A separate paragraph for parents/guardians was included in the introductory script. Once parental permission was granted, the FI approached the youth and introduced the study using the script to obtain the youth's agreement to participate. Parents were then asked to leave the interview setting to ensure the confidentiality of the youth's responses. When ready, the FI and the youth began the interview.

6.4.2 Computer Assisted Interviews (CAI)

The CAI interview began in the CAPI mode (computer-assisted personal interviewing), with the FI reading the questions from the computer screen and entering the respondent's replies into the computer. After completing the Reference Date Calendar, the FI explained to the respondent how to use the computer for the ACASI (audio computer-assisted self-interviewing) sections. Utilizing ACASI methodology for the sensitive drug usage questions enhanced privacy since the respondent listened to the pre-recorded questions through the headphones and entered the responses directly into the computer. Beginning with a practice session which introduced the various computer keys used during the interview, the respondent then proceeded through the interview. Four times during the ACASI portion of the interview, the respondent was instructed to ask the interviewer for a specific picture pill card designed to aid respondent recall. When the respondent was finished with the ACASI portion, the interviewer once again took charge of the computer, asking additional demographic questions as well as health care, insurance, and income questions. During both the beginning and ending CAPI portions, showcards were utilized to assist respondents in answering the questions.

The average CAI administration times overall and for the various sections of the CAI interview by respondent age (youth 12-17 or adult 18+) and survey year are given in Table s 6.1 through 6.29. Please note that the total number of interviews included varies between tables due to suspect timing data, such as missing timing data, unresolved breakoff times or extreme values. Sections categorized as having suspect timing data were not included in the analysis, though unaffected sections were included. Consider an example case: if timing for alcohol was suspect, then the timing data for alcohol, total ACASI, total core, and total time were excluded. Other non-suspect sections for that case, including other drugs such as cigarettes, marijuana, etc., were included in the analysis. Also note that changes to the questionnaire content for 2000 (inclusion of new modules, changes to module ordering) affected the availability of comparable 1999 statistics.

6.4.3 End of the Interview Procedures

After the last interview question, the interview process involved several final steps. FIs had to:

• prepare the Verification Form and ask the respondent to complete the remaining items on the form;
• seal the completed Verification Form in a postage-paid envelope addressed to RTI;
• complete the FI Observation Questions;
• enter the final result code in the Newton;
• gather all interview equipment and materials; and
• thank the respondent.

All completed Reference Date Calendars were sent weekly to the field supervisor. Sealed Verification Form envelopes were mailed to RTI as soon as possible. Each night FIs transmitted interview data to RTI.

6.5 Data Collection Management

Project management on this massive study can be summed up in one word: communication. For instance:

• Interviewers throughout the country reported to their Field Supervisor at least once each week to discuss production, problems encountered and possible resolutions, feedback on past work, plans for the next week, and any administrative issues.
• Field Supervisors each reported to their Regional Supervisor weekly, discussing production, costs, goals, staffing, and other administrative issues.
• Each Regional Director held a weekly meeting with his/her staff of Regional Supervisors to share project news and goals while addressing any problems within the region.
• All Regional Directors met each week with the National Field Director and the Project Director.
• All Directors and other key management staff met weekly with SAMHSA representatives.

Although the more formal meetings were held weekly, staff communicated almost constantly through the widespread use of e-mail. This management tool increased awareness of project issues by effectively passing information through the various management levels. Added for 2000 was the capability to send messages to interviewers using a one-way electronic messaging system on the Gateway laptop.

With the implementation of the Web-based project Case Management System, all management staff had access to a tremendous amount of information on the status of events in the field. Additional details on the CMS are provided in Section 8.2.

Another helpful management tool was the quarterly Performance Improvement Plan. At the end of each quarter of data collection, FSs developed specific plans in an effort to target particularly troublesome areas for improvement during the next quarter. Plans included the following information:

• A statement of the problem/situation to be addressed.
• A diagnosis of the problem in the past.
• Projected or desired outcomes.
• Specific efforts designed to accomplish these outcomes.

RSs assisted in the plan development and monitored the results of the plan's implementation.

6.6 Controlled Access Procedures

At times during the data collection process, interviewers had difficulty gaining access to particular SDUs. Interviewers with challenging circumstances were instructed to be observant, resourceful, and keep their supervisors informed of the situation. Additional suggestions taken from FS experience or from RTI's "Guide to Controlled Access Situations" were discussed. Talks with managers/owners generally centered on the importance of the study, SAMHSA and RTI's emphasis on confidentiality, and the right of the individuals to make a personal decision about participation. Supervisors sometimes contacted managers/owners directly to answer questions or concerns.

Due to prior efforts by staff who listed the dwelling units, many access problems were resolved readily. Listers recorded contact information and other steps followed to secure access so that interviewers could follow the same strategies or build on already-established relations. Supervisors at the listing stage used special reports on the CMS to monitor access situations; supervisors for screening and interviewing used the same reports and recorded additional information to update the reports.

For continuing problems, RTI had a system to generate individualized letters and packets of information about the project. When required, FIs and FSs provided basic information to RSs, who then requested the packets. Upon receiving the request, specialists at RTI prepared a cover letter and assembled materials to fit the situation. The packet was often sent via Federal Express to increase the importance placed on the contents and ensure timely delivery. Starting in April, 2000, a video was available for inclusion in the packets which further explained the need for access.

For persistent problem situations not resolved through FS/FI efforts or the letters/packets, "Please Call Us" letters were sent. Special care was taken that calls resulting from the letters were directed to the authorized RS or FS to set up an appointment so the FI could return and complete screening, or, in dire situations and with permission, screening information could be obtained by the FS or RS over the telephone.

Occasionally controlled access problems required assistance beyond the RS level so Regional Directors—and sometimes even the National Field Director became involved.

6.7 Refusal Conversion Procedures

More often than desired, potential respondents exercised their "right to refuse to participate." The following were in place to try to prevent refusal situations:

• The 2000 Field Interviewer Manual gave specific instructions to the FIs for introducing both themselves and the study. Additionally, an entire chapter discussed "Obtaining Participation" and listed the tools available to field staff along with tips for answering questions and overcoming objections.
• During New-to-Project FI training, two sections of the guide covered details for contacting dwelling units and how to deal with reluctant respondents and difficult situations. During exercises and mock interviews, trainees were able to practice answering questions and using letters and handouts to obtain cooperation.
• During the 2-day Veteran FI training, most of one afternoon was spent discussing various situations FIs often encounter, and ways to effectively deal with the situations. A special video showed various scenarios to help FIs visualize successful refusal aversion/conversion approaches.
• All aspects of the NHSDA were designed to exude professionalism and thus enhance the legitimacy of the project. All materials provided to the public were developed carefully. Interviewers were instructed to always behave professionally and courteously.

In refusal situations, staff followed these steps:

• Detailed notes describing the situation were recorded in a Refusal Report on the Newton. FIs classified the refusal according to one of seven categories.
• After transmission from the Newton to RTI, the category of refusal and any notes were then available to the supervisor on the Web-based CMS. The FI and FS could then discuss the situation, with the FS suggesting additional tactics if necessary.
• Once the refusal situation was discussed, a refusal conversion letter was sent (if appropriate). On the CMS, the FS selected a specific letter based on the stage of the case (screening or interviewing), the category of the reason for the refusal (too busy, confidentiality concerns, etc.) and, for interviewing, the person to be addressed (the actual respondent or the parent of a selected youth). The FS could also delete the request for the letter (in situations where a letter would not be helpful or could not be delivered) or release the letter for automatic production and mailing.
• The interviewer returned to the DU to try again with other tactics.
• Cases could be transferred to a different interviewer if necessary.
• Supervisors were available to reluctant respondents to discuss the importance of participation.

6.8 Problems Encountered

6.8.1 Size and Scope of the Project

By selecting areas throughout the entire country, many different types of situations arose that had to be resolved. With the large staff required by the size of the project, communication was vitally important yet it was challenging to ensure that tips and suggestions were consistently conveyed to all staff.

6.8.2 Interviewing Staff Attrition

The constant turnover of interviewing staff meant there were not enough interviewers to adequately cover the assignments in all areas. Once replacement staff were in place, FSs underwent the learning curve process with these new FIs rather than being able to build on experience FIs had gained in the field. The continued attrition caused FSs to spend considerable time dealing with staffing issues (recruiting, hiring, more intense supervision of new employee, etc.) and less time on appropriately managing the most difficult cases.

6.8.3 Refusals

While refusals at the screening and interview level have historically been a problem for the NHSDA (as with all national-level household surveys), refusals have become a more significant problem. Some factors contributing to the rise in refusals and corresponding decline in response rates were:

• Very favorable economic conditions meant members of selected households were employed at higher levels than in the past, at home less and less inclined to devote the necessary time to participate.
• A larger percentage of cases involved households with two persons selected for interview. Historically, response rates in households with two respondents are lower due to more frequent refusals by the second selected individual.
• Low unemployment rates caused a shortage of qualified and interested FI candidates to fill FI position openings. Those hired were often inexperienced.
• The sophisticated CMS allowed for increased monitoring of questionable FI activities resulting in fewer fraudulent cases being submitted.

6.8.4 Typical Data Collection Concerns

As is common in any large field data collection effort, staff encountered problems such as respondent availability, dwelling unit access (controlled or otherwise restricted), and high crime neighborhoods. Additionally, the use of escorts to increase interviewer comfort levels in unsafe areas had an impact on respondent reactions.

6.8.5 Newton

Using the Newton for electronic screening was a great use of new technology, but the Newton had its drawbacks:

• It was sensitive to a variety of weather conditions (and all types were encountered).
• As it became full of data, its response time slowed down and tried respondents' patience.
• The new technology created a confidence issue for new staff who were unaccustomed to using computers.
• Concentrating on the device meant less eye contact with the respondent, which in turn made it tougher to establish good rapport.

6.8.6 CAI Patches

During the course of data collection for 2000, several problems were found with the logic programmed into the CAI instrument. Modifications were made to the programs loaded on the FI laptops using CAI patches. To receive the patch, FIs simply transmitted and the new program files were installed automatically. Patches issued during the year included:

Table 6.1 2000 NHSDA Timing Data: Total Interview Time (Minutes) with FI Debrief

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	22,377	24,058	35,555	44,037
Summary Statistics (in Minutes)
Mean ()	55.1	55.9	50.2	48.1
Variance (2)	276.1	285.4	329.8	277.0
Standard Deviation ()	16.6	16.9	18.2	16.6
Quartiles
Maximum	201.3	180.0	224.8	208.6
Q3	64.8	65.5	59.0	56.2
Median	53.4	53.7	47.3	45.2
Q1	43.4	43.9	37.7	36.6
Minimum	9.7	11.8	9.9	10.4
Range	191.6	168.2	214.9	198.2
Mode	37.0	39.5	40.6	42.3
Percentiles
99%	103.5	106.1	108.9	101.8
95%	84.3	86.5	83.9	79.4
90%	76.6	78.0	73.1	69.3
10%	35.7	36.5	30.6	30.3
5%	31.8	32.6	26.8	27.1
1%	23.8	26.1	20.2	21.7
Extremes
5 Highest Values
(Highest)	201.3	180.0	224.8	208.6
	190.0	167.2	206.6	187.0
	172.3	150.3	205.7	184.8
	166.8	147.6	204.1	184.0
	161.1	147.3	202.4	171.3
5 Lowest Values
	12.1	16.3	10.5	12.8
	11.0	16.1	10.4	12.4
	10.5	15.8	10.2	11.9
	10.3	15.5	9.9	10.8
(Lowest)	9.7	11.8	9.9	10.4
Note: Time recording begins at screen STARTUP in the Introduction and stops recording after screen FIEXIT in the FI Debrief Module.

Table 6.2 2000 NHSDA Timing Data: Introduction

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,289	25,671	41,209	45,925
Summary Statistics (in Minutes)
Mean ()	3.8	3.5	4.0	3.8
Variance (2)	5.6	5.4	6.7	7.0
Standard Deviation ()	2.4	2.3	2.6	2.6
Quartiles
Maximum	35.6	42.2	47.6	42.9
Q3	4.9	4.5	5.0	4.8
Median	3.4	3.1	3.4	3.3
Q1	2.2	2.0	2.2	2.1
Minimum	0.4	0.3	0.3	0.4
Range	35.3	41.9	47.3	42.5
Mode	2.1	2.4	3.8	2.4
Percentiles
99%	11.8	11.2	13.0	13.5
95%	7.9	7.6	8.4	8.4
90%	6.5	6.3	6.9	6.8
10%	1.4	1.3	1.5	1.4
5%	1.0	1.0	1.2	1.1
1%	0.7	0.7	0.8	0.8
Extremes
5 Highest Values
(Highest)	35.6	42.2	47.6	42.9
	31.7	40.1	38.9	41.5
	30.4	32.0	38.8	33.2
	29.8	30.9	38.6	33.0
	28.9	29.2	36.8	31.6
5 Lowest Values
	0.4	0.4	0.5	0.5
	0.4	0.4	0.5	0.5
	0.4	0.4	0.5	0.5
	0.4	0.3	0.5	0.4
(Lowest)	0.4	0.3	0.3	0.4
Note: Time recording begins at screen STARTUP in the Introduction and stops recording after screen CALENDAR in the Core Demographics Module.

Table 6.3 2000 NHSDA Timing Data: Total ACASI

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	23,022	24,604	36,514	45,113
Summary Statistics (in Minutes)
Mean ()	38.3	39.3	33.2	29.6
Variance (2)	190.6	209.0	222.5	176.2
Standard Deviation ()	13.8	14.5	14.9	13.3
Quartiles
Maximum	202.0	154.2	193.9	173.3
Q3	46.1	47.6	39.9	35.6
Median	36.5	37.2	30.4	26.9
Q1	28.6	28.8	23.1	20.4
Minimum	5.2	5.2	3.1	3.9
Range	196.8	149.0	190.8	169.4
Mode	26.1	33.4	20.9	24.3
Percentiles
99%	79.2	82.7	82.9	74.1
95%	62.5	66.0	61.5	54.9
90%	55.9	58.4	51.9	46.6
10%	22.7	22.9	18.0	16.0
5%	19.5	19.8	15.1	13.7
1%	13.1	15.0	9.8	10.2
Extremes
5 Highest Values
(Highest)	202.0	154.2	193.9	173.3
	190.2	130.7	188.8	161.1
	164.2	126.1	183.1	143.6
	153.9	120.9	180.2	138.1
	152.9	119.4	168.0	136.4
5 Lowest Values
	5.7	7.7	4.5	5.0
	5.7	6.7	4.3	4.9
	5.3	5.9	3.8	4.8
	5.2	5.6	3.6	4.0
(Lowest)	5.2	5.2	3.1	3.9
Note: Time recording begins at screen INTROACASI in the Tutorial Module and stops recording after screen ENDAUDIO in either the Youth Experience, Social Environment or Parenting Module.

Table 6.4 2000 NHSDA Timing Data: Tutorial Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,335	25,710	41,305	46,025
Summary Statistics (in Minutes)
Mean ()	2.6	2.4	2.6	2.3
Variance (2)	1.9	1.8	2.9	2.5
Standard Deviation ()	1.4	1.3	1.7	1.6
Quartiles
Maximum	27.7	25.5	29.8	29.8
Q3	3.5	3.2	3.3	3.0
Median	2.5	2.1	2.2	1.9
Q1	1.7	1.4	1.5	1.3
Minimum	0.0	0.1	0.1	0.1
Range	27.6	25.4	29.8	29.7
Mode	1.6	1.3	1.8	1.5
Percentiles
99%	6.6	6.1	8.2	7.4
95%	4.9	4.6	5.5	5.1
90%	4.3	4.0	4.5	4.2
10%	1.1	0.9	0.9	0.8
5%	0.8	0.7	0.6	0.6
1%	0.4	0.4	0.3	0.4
Extremes
5 Highest Values
(Highest)	27.7	25.5	29.8	29.8
	24.4	21.6	28.8	29.1
	18.1	21.3	28.5	27.1
	17.8	21.2	27.6	26.2
	17.3	20.7	26.3	25.4
5 Lowest Values
	0.1	0.2	0.1	0.2
	0.1	0.2	0.1	0.2
	0.1	0.2	0.1	0.1
	0.0	0.1	0.1	0.1
(Lowest)	0.0	0.1	0.1	0.1
Note: Time recording begins at screen INTRO1 in the Tutorial Module and stops recording after screen ANYQUES in the Tutorial.

Table 6.5 2000 NHSDA Timing Data: Total Core Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,218	25,631	41,105	45,865
Summary Statistics (in Minutes)
Mean ()	12.1	11.9	12.5	12.6
Variance (2)	33.1	34.9	44.0	47.3
Standard Deviation ()	5.7	5.9	6.6	6.9
Quartiles
Maximum	70.9	72.5	88.9	109.3
Q3	15.3	15.1	15.4	15.4
Median	11.2	10.8	11.2	11.0
Q1	7.9	7.6	8.0	7.9
Minimum	0.5	0.8	0.7	0.9
Range	70.3	71.7	88.2	108.4
Mode	8.3	9.1	9.1	10.9
Percentiles
99%	29.5	29.8	34.5	35.5
95%	22.4	23.1	25.1	25.9
90%	19.6	19.9	20.9	21.5
10%	5.7	5.6	5.8	5.8
5%	4.5	4.6	4.6	4.7
1%	2.3	3.1	2.4	3.0
Extremes
5 Highest Values
(Highest)	70.9	72.5	88.9	109.3
	56.4	61.7	88.9	100.0
	53.1	57.4	76.7	95.0
	51.5	55.1	76.1	85.3
	50.8	53.8	74.5	79.6
5 Lowest Values
	0.7	1.3	0.8	1.0
	0.7	1.2	0.8	1.0
	0.7	1.0	0.8	1.0
	0.6	0.8	0.8	1.0
(Lowest)	0.5	0.8	0.7	0.9
Note: Time recording begins at screen LEADCIG in the Tobacco Module and stops recording after screen SV13 in the Sedative Module.

Table 6.6 2000 NHSDA Timing Data: Total Tobacco Sections

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,295	25,688	41,271	45,971
Summary Statistics (in Minutes)
Mean ()	3.0	2.8	3.2	3.1
Variance (2)	3.0	3.1	4.4	4.8
Standard Deviation ()	1.7	1.8	2.1	2.2
Quartiles
Maximum	30.3	25.1	34.5	41.5
Q3	3.9	3.8	4.1	4.0
Median	2.7	2.4	2.8	2.6
Q1	1.7	1.5	1.8	1.6
Minimum	0.1	0.2	0.1	0.1
Range	30.2	25.0	34.4	41.4
Mode	1.5	1.2	2.5	2.0
Percentiles
99%	8.5	8.6	10.5	10.6
95%	6.0	5.8	6.9	7.0
90%	5.0	4.9	5.6	5.6
10%	1.2	1.1	1.1	1.0
5%	1.0	0.9	0.8	0.7
1%	0.5	0.6	0.3	0.4
Extremes
5 Highest Values
(Highest)	30.3	25.1	34.5	41.5
	22.6	25.0	33.2	37.5
	21.9	22.4	31.4	35.4
	21.6	20.3	30.0	31.9
	19.9	19.7	29.0	31.5
5 Lowest Values
	0.1	0.2	0.1	0.1
	0.1	0.2	0.1	0.1
	0.1	0.2	0.1	0.1
	0.1	0.2	0.1	0.1
(Lowest)	0.1	0.2	0.1	0.1
Note: Time recording begins at screen LEADCIG in the Tobacco Module and stops recording after screen CG43 in the Tobacco Module.

Table 6.7 2000 NHSDA Timing Data: Alcohol Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,345	25,715	41,316	46,034
Summary Statistics (in Minutes)
Mean ()	1.1	1.1	1.8	1.9
Variance (2)	1.4	1.5	2.0	2.2
Standard Deviation ()	1.2	1.2	1.4	1.5
Quartiles
Maximum	16.4	19.5	28.4	27.2
Q3	1.6	1.6	2.4	2.5
Median	0.5	0.6	1.7	1.7
Q1	0.2	0.2	0.8	0.9
Minimum	0.0	0.0	0.0	0.0
Range	16.4	19.5	28.3	27.2
Mode	0.1	0.1	0.1	0.1
Percentiles
99%	5.1	5.3	6.5	6.9
95%	3.4	3.5	4.2	4.4
90%	2.7	2.7	3.4	3.5
10%	0.1	0.1	0.3	0.3
5%	0.1	0.1	0.1	0.1
1%	0.1	0.1	0.1	0.1
Extremes
5 Highest Values
(Highest)	16.4	19.5	28.4	27.2
	16.2	16.7	28.0	26.9
	15.1	15.7	27.2	23.8
	14.3	14.4	27.1	23.5
	13.3	13.9	23.9	23.1
5 Lowest Values
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
(Lowest)	0.0	0.0	0.0	0.0
Note: Time recording begins at screen ALCINTR1 in the Alcohol Module and stops recording after screen ALCC30 in the Alcohol Module.

Table 6.8 2000 NHSDA Timing Data: Marijuana Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,343	25,716	41,330	46,042
Summary Statistics (in Minutes)
Mean ()	0.4	0.4	0.4	0.4
Variance (2)	0.3	0.3	0.3	0.3
Standard Deviation ()	0.6	0.5	0.5	0.6
Quartiles
Maximum	24.3	18.4	20.0	26.3
Q3	0.3	0.3	0.5	0.5
Median	0.2	0.2	0.3	0.3
Q1	0.1	0.1	0.1	0.1
Minimum	0.0	0.0	0.0	0.0
Range	24.3	18.4	20.0	26.3
Mode	0.1	0.1	0.1	0.1
Percentiles
99%	2.4	2.4	2.3	2.4
95%	1.4	1.4	1.3	1.3
90%	1.0	1.0	0.9	0.9
10%	0.1	0.1	0.1	0.1
5%	0.1	0.1	0.1	0.1
1%	0.0	0.1	0.0	0.1
Extremes
5 Highest Values
(Highest)	24.3	18.4	20.0	26.3
	23.8	16.7	15.8	19.4
	20.7	15.1	12.5	18.9
	11.9	9.2	12.3	17.9
	9.9	9.0	12.2	15.6
5 Lowest Values
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
(Lowest)	0.0	0.0	0.0	0.0
Note: Time recording begins at screen MRJINTRO in the Marijuana Module and stops recording after screen MJCC16 in the Marijuana Module.

Table 6.9 2000 NHSDA Timing Data: Cocaine & Crack Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,337	25,707	41,324	46,035
Summary Statistics (in Minutes)
Mean ()	0.1	0.1	0.2	0.2
Variance (2)	0.1	0.1	0.2	0.2
Standard Deviation ()	0.2	0.3	0.4	0.4
Quartiles
Maximum	9.5	11.7	29.7	23.7
Q3	0.1	0.1	0.2	0.2
Median	0.1	0.1	0.1	0.1
Q1	0.1	0.1	0.1	0.1
Minimum	0.0	0.0	0.0	0.0
Range	9.5	11.7	29.7	23.7
Mode	0.1	0.1	0.1	0.1
Percentiles
99%	1.3	1.2	1.8	1.7
95%	0.3	0.3	0.8	0.7
90%	0.2	0.2	0.4	0.4
10%	0.1	0.1	0.1	0.1
5%	0.1	0.1	0.1	0.1
1%	0.0	0.0	0.0	0.0
Extremes
5 Highest Values
(Highest)	9.5	11.7	29.7	23.7
	5.4	9.3	20.1	18.3
	5.4	6.8	15.9	14.4
	4.9	5.7	15.7	13.6
	4.6	5.7	12.6	12.6
5 Lowest Values
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
(Lowest)	0.0	0.0	0.0	0.0
Note: Time recording begins at screen COCINTRO in the Cocaine Module and stops recording after screen CKCC16 in the Crack Module.

Table 6.10 2000 NHSDA Timing Data: Heroin Section

Table 6.10 2000 NHSDA Timing Data: Heroin Section
Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,340	25,713	41,322	46,044
Summary Statistics (in Minutes)
Mean ()	0.4	0.4	0.3	0.3
Variance (2)	0.2	0.1	0.2	0.2
Standard Deviation ()	0.4	0.4	0.4	0.4
Quartiles
Maximum	20.4	13.0	29.8	24.9
Q3	0.6	0.5	0.3	0.3
Median	0.3	0.2	0.2	0.2
Q1	0.1	0.1	0.1	0.1
Minimum	0.0	0.0	0.0	0.0
Range	20.4	12.9	29.8	24.9
Mode	0.1	0.1	0.1	0.1
Percentiles
99%	1.2	1.3	1.3	1.3
95%	0.9	1.0	0.9	1.0
90%	0.9	0.9	0.7	0.7
10%	0.1	0.1	0.1	0.1
5%	0.1	0.1	0.1	0.1
1%	0.0	0.1	0.0	0.1
Extremes
5 Highest Values
(Highest)	20.4	13.0	29.8	24.9
	19.1	8.7	19.4	18.4
	11.3	8.0	19.2	14.6
	9.2	7.4	17.0	13.3
	8.4	6.6	15.0	12.7
5 Lowest Values
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
(Lowest)	0.0	0.0	0.0	0.0
Note: Time recording begins at screen HEINTRO in the Heroin Module and stops recording after screen HECC16 in the Heroin Module.

Table 6.11 2000 NHSDA Timing Data: Hallucinogen Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,348	25,714	41,334	46,039
Summary Statistics (in Minutes)
Mean ()	1.0	1.1	0.9	1.0
Variance (2)	0.6	0.7	0.8	0.9
Standard Deviation ()	0.8	0.8	0.9	1.0
Quartiles
Maximum	22.1	28.8	29.4	29.7
Q3	1.4	1.3	1.1	1.2
Median	0.9	0.8	0.7	0.7
Q1	0.5	0.5	0.5	0.5
Minimum	0.0	0.1	0.0	0.1
Range	22.1	28.8	29.3	29.6
Mode	0.6	0.5	0.5	0.5
Percentiles
99%	3.4	3.7	3.7	4.1
95%	2.4	2.5	2.5	2.7
90%	2.0	2.1	1.9	2.0
10%	0.4	0.4	0.3	0.3
5%	0.3	0.3	0.3	0.3
1%	0.2	0.2	0.2	0.2
Extremes
5 Highest Values
(Highest)	22.1	28.8	29.4	29.7
	15.5	24.3	26.8	27.0
	13.6	17.1	24.5	26.3
	13.4	15.3	24.0	25.3
	12.3	15.0	22.9	23.9
5 Lowest Values
	0.1	0.1	0.0	0.1
	0.0	0.1	0.0	0.1
	0.0	0.1	0.0	0.1
	0.0	0.1	0.0	0.1
(Lowest)	0.0	0.1	0.0	0.1
Note: Time recording begins at screen HALINTRO in the Hallucinogen Module and stops recording after screen LSCC42 in the Hallucinogen Module.

Table 6.12 2000 NHSDA Timing Data: Inhalant Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,338	25,708	41,326	46,020
Summary Statistics (in Minutes)
Mean ()	2.1	2.1	1.8	1.9
Variance (2)	1.4	1.5	1.5	1.6
Standard Deviation ()	1.2	1.2	1.2	1.3
Quartiles
Maximum	29.2	27.8	27.5	28.8
Q3	2.6	2.7	2.3	2.3
Median	1.9	1.9	1.6	1.6
Q1	1.3	1.3	1.1	1.1
Minimum	0.1	0.1	0.0	0.1
Range	29.2	27.7	27.5	28.7
Mode	1.8	1.3	1.2	1.5
Percentiles
99%	5.8	5.9	5.9	6.0
95%	4.0	4.1	3.8	4.0
90%	3.4	3.5	3.1	3.2
10%	0.8	0.8	0.7	0.8
5%	0.6	0.7	0.6	0.6
1%	0.3	0.4	0.3	0.3
Extremes
5 Highest Values
(Highest)	29.2	27.8	27.5	28.8
	22.2	23.2	26.5	28.8
	22.1	22.0	25.6	27.8
	21.4	21.8	23.4	27.7
	20.3	19.9	23.1	24.7
5 Lowest Values
	0.1	0.1	0.1	0.1
	0.1	0.1	0.1	0.1
	0.1	0.1	0.1	0.1
	0.1	0.1	0.1	0.1
(Lowest)	0.1	0.1	0.0	0.1
Note: Time recording begins at screen INHINTRO in the Inhalant Module and stops recording after screen INCC16 in the Inhalant Module.

Table 6.13 2000 NHSDA Timing Data: Total Pill Sections

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,318	25,685	41,255	46,001
Summary Statistics (in Minutes)
Mean ()	4.0	4.0	3.8	3.9
Variance (2)	6.2	6.6	7.7	8.0
Standard Deviation ()	2.5	2.6	2.8	2.8
Quartiles
Maximum	30.9	35.2	50.1	46.8
Q3	5.3	5.2	4.8	4.8
Median	3.5	3.4	3.1	3.1
Q1	2.3	2.2	2.0	2.0
Minimum	0.1	0.1	0.1	0.2
Range	30.7	35.0	50.0	46.6
Mode	2.3	2.2	2.7	2.3
Percentiles
99%	11.8	12.2	13.5	13.6
95%	8.6	9.0	9.2	9.6
90%	7.3	7.4	7.2	7.3
10%	1.4	1.5	1.3	1.3
5%	1.1	1.1	1.0	1.0
1%	0.5	0.7	0.5	0.6
Extremes
5 Highest Values
(Highest)	30.9	35.2	50.1	46.8
	28.1	32.9	45.3	42.4
	28.0	31.4	40.9	36.4
	25.3	26.7	39.1	35.4
	24.8	26.3	36.3	34.7
5 Lowest Values
	0.1	0.2	0.2	0.2
	0.1	0.2	0.2	0.2
	0.1	0.2	0.1	0.2
	0.1	0.2	0.1	0.2
(Lowest)	0.1	0.1	0.1	0.2
Note: Time recording begins at screen INTRPILL in the Pain Relievers Module and stops recording after screen SV13 in the Sedative Module.

Table 6.14 2000 NHSDA Timing Data: Total Non-Core Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	23,170	24,707	36,740	45,348
Summary Statistics (in Minutes)
Mean ()	17.8	23.5	12.8	13.2
Variance (2)	37.8	78.2	33.7	39.7
Standard Deviation ()	6.2	8.8	5.8	6.3
Quartiles
Maximum	68.7	87.2	89.8	82.5
Q3	21.0	28.2	15.1	15.7
Median	17.0	22.2	11.6	11.8
Q1	13.7	17.3	9.0	9.0
Minimum	0.7	2.1	0.4	0.8
Range	68.0	85.1	89.3	81.7
Mode	16.0	19.1	9.5	11.2
Percentiles
99%	36.4	50.7	33.2	35.8
95%	29.4	39.8	23.7	25.0
90%	25.9	35.1	19.9	20.9
10%	11.1	13.7	7.1	7.1
5%	9.6	11.8	6.1	6.1
1%	6.2	8.4	4.0	4.6
Extremes
5 Highest Values
(Highest)	68.7	87.2	89.8	82.5
	57.3	80.5	84.6	81.9
	56.9	77.4	72.9	79.1
	55.7	77.3	67.2	76.8
	54.5	76.1	63.0	76.6
5 Lowest Values
	1.3	3.3	0.7	1.3
	1.2	3.2	0.7	1.2
	1.1	3.0	0.6	1.2
	1.0	2.3	0.6	1.1
(Lowest)	0.7	2.1	0.4	0.8
Note: Time recording begins at screen INTROSD in the Special Drugs Module and stops recording after screen ENDAUDIO in either the Youth Experience, Social Environment or Parenting Module.

Table 6.15 2000 NHSDA Timing Data: Special Drugs Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,305	25,705	41,257	46,028
Summary Statistics (in Minutes)
Mean ()	0.6	0.6	0.6	0.6
Variance (2)	0.3	0.2	0.3	0.3
Standard Deviation ()	0.5	0.4	0.6	0.6
Quartiles
Maximum	26.9	24.5	27.9	27.1
Q3	0.7	0.7	0.7	0.7
Median	0.5	0.5	0.5	0.5
Q1	0.3	0.3	0.3	0.3
Minimum	0.0	0.0	0.0	0.0
Range	26.9	24.5	27.9	27.1
Mode	0.3	0.3	0.3	0.3
Percentiles
99%	1.8	1.8	2.3	2.4
95%	1.1	1.1	1.1	1.2
90%	0.9	0.9	0.9	0.9
10%	0.2	0.2	0.2	0.2
5%	0.2	0.2	0.2	0.2
1%	0.1	0.1	0.1	0.1
Extremes
5 Highest Values
(Highest)	26.9	24.5	27.9	27.1
	26.5	14.5	24.1	24.3
	24.5	12.2	22.5	23.3
	24.1	11.9	22.5	22.4
	14.1	11.6	22.4	21.5
5 Lowest Values
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
(Lowest)	0.0	0.0	0.0	0.0
Note: Time recording begins at screen INTROSD in the Special Drugs Module and stops recording after screen SD16SP in the Special Drugs Module.

Table 6.16 2000 NHSDA Timing Data: Risk/Availability Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,304	25,691	41,231	45,987
Summary Statistics (in Minutes)
Mean ()	3.2	3.3	3.2	3.2
Variance (2)	2.3	2.5	3.2	3.5
Standard Deviation ()	1.5	1.6	1.8	1.9
Quartiles
Maximum	29.4	29.5	29.5	29.8
Q3	3.8	3.9	3.7	3.8
Median	2.9	2.9	2.8	2.8
Q1	2.3	2.3	2.1	2.1
Minimum	0.1	0.3	0.1	0.3
Range	29.3	29.3	29.4	29.5
Mode	2.6	2.7	2.4	2.3
Percentiles
99%	8.4	8.8	9.7	10.2
95%	5.8	6.0	6.4	6.7
90%	4.9	5.0	5.1	5.2
10%	1.8	1.8	1.7	1.7
5%	1.5	1.6	1.4	1.5
1%	0.9	1.2	0.9	1.1
Extremes
5 Highest Values
(Highest)	29.4	29.5	29.5	29.8
	27.6	28.3	29.1	29.1
	25.3	28.2	28.9	28.2
	25.2	26.3	28.9	26.8
	22.9	25.0	27.2	26.1
5 Lowest Values
	0.1	0.5	0.1	0.4
	0.1	0.5	0.1	0.3
	0.1	0.4	0.1	0.3
	0.1	0.3	0.1	0.3
(Lowest)	0.1	0.3	0.1	0.3
Note: Time recording begins at screen RKQ1 in the Risk/Availability Module and stops recording after screen RK04d in the Risk/Availability Module.

Table 6.17 2000 NHSDA Timing Data: Drug Dependence & Abuse Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	23,685	25,083	37,001	45,749
Summary Statistics (in Minutes)
Mean ()	1.2	1.2	2.1	2.5
Variance (2)	3.8	5.7	4.6	7.7
Standard Deviation ()	2.0	2.4	2.1	2.8
Quartiles
Maximum	45.6	35.4	51.6	55.5
Q3	1.9	1.7	2.9	3.7
Median	0.0	0.0	1.7	2.0
Q1	0.0	0.0	1.0	0.0
Minimum	0.0	0.0	0.0	0.0
Range	45.6	35.4	51.6	55.5
Mode	0.0	0.0	0.0	0.0
Percentiles
99%	7.9	10.5	9.3	12.2
95%	4.8	6.1	5.5	7.4
90%	3.6	4.3	4.3	5.7
10%	0.0	0.0	0.0	0.0
5%	0.0	0.0	0.0	0.0
1%	0.0	0.0	0.0	0.0
Extremes
5 Highest Values
(Highest)	45.6	35.4	51.6	55.5
	40.7	32.5	48.9	46.4
	33.7	31.9	43.6	45.8
	30.9	28.5	43.6	45.4
	30.1	28.0	42.8	44.3
5 Lowest Values
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
	0.0	0.0	0.0	0.0
(Lowest)	0.0	0.0	0.0	0.0
Note: Time recording begins at screen INTRODR in the Drug Dependence & Abuse Module and stops recording after screen DRSV22 in the Drug Dependence & Abuse Module.

Table 6.18 2000 NHSDA Timing Data: Special Topics, Drug Treatment & Health Care Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	N/A	25,567	N/A	45,844
Summary Statistics (in Minutes)
Mean ()	N/A	1.5	N/A	1.5
Variance (2)	N/A	1.4	N/A	1.9
Standard Deviation ()	N/A	1.2	N/A	1.4
Quartiles
Maximum	N/A	23.8	N/A	37.1
Q3	N/A	1.7	N/A	1.7
Median	N/A	1.3	N/A	1.2
Q1	N/A	0.9	N/A	0.9
Minimum	N/A	0.1	N/A	0.1
Range	N/A	23.7	N/A	37.0
Mode	N/A	1.0	N/A	0.9
Percentiles
99%	N/A	6.6	N/A	7.2
95%	N/A	3.2	N/A	3.4
90%	N/A	2.5	N/A	2.6
10%	N/A	0.7	N/A	0.7
5%	N/A	0.6	N/A	0.6
1%	N/A	0.4	N/A	0.4
Extremes
5 Highest Values
(Highest)	N/A	23.8	N/A	37.1
	N/A	21.0	N/A	31.9
	N/A	19.4	N/A	30.6
	N/A	19.3	N/A	30.5
	N/A	17.6	N/A	29.6
5 Lowest Values
	N/A	0.1	N/A	0.1
	N/A	0.1	N/A	0.1
	N/A	0.1	N/A	0.1
	N/A	0.1	N/A	0.1
(Lowest)	N/A	0.1	N/A	0.1
Note: Time recording begins at screen INTROSP in the Special Topics Module and stops recording after screen HLTH05 in the Health Care Module.

Table 6.19 2000 NHSDA Timing Data: Adult Mental Health Service Utilization Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	N/A	N/A	N/A	46,019
Summary Statistics (in Minutes)
Mean ()	N/A	N/A	N/A	0.9
Variance (2)	N/A	N/A	N/A	0.8
Standard Deviation ()	N/A	N/A	N/A	0.9
Quartiles
Maximum	N/A	N/A	N/A	27.8
Q3	N/A	N/A	N/A	1.1
Median	N/A	N/A	N/A	0.7
Q1	N/A	N/A	N/A	0.5
Minimum	N/A	N/A	N/A	0.0
Range	N/A	N/A	N/A	27.8
Mode	N/A	N/A	N/A	0.5
Percentiles
99%	N/A	N/A	N/A	4.4
95%	N/A	N/A	N/A	2.3
90%	N/A	N/A	N/A	1.7
10%	N/A	N/A	N/A	0.4
5%	N/A	N/A	N/A	0.3
1%	N/A	N/A	N/A	0.2
Extremes
5 Highest Values
(Highest)	N/A	N/A	N/A	27.8
	N/A	N/A	N/A	25.1
	N/A	N/A	N/A	24.6
	N/A	N/A	N/A	20.9
	N/A	N/A	N/A	20.3
5 Lowest Values
	N/A	N/A	N/A	0.0
	N/A	N/A	N/A	0.0
	N/A	N/A	N/A	0.0
	N/A	N/A	N/A	0.0
(Lowest)	N/A	N/A	N/A	0.0
Note: Time recording begins at screen ADINTRO in the Adult Mental Health Service Utilization Module and stops recording after screen ADMENT27 in the Adult Mental Health Service Utilization Module.

Table 6.20 2000 NHSDA Timing Data: Social Environment Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	N/A	N/A	41,077	45,899
Summary Statistics (in Minutes)
Mean ()	N/A	N/A	5.8	4.2
Variance (2)	N/A	N/A	8.0	5.9
Standard Deviation ()	N/A	N/A	2.8	2.4
Quartiles
Maximum	N/A	N/A	30.0	29.8
Q3	N/A	N/A	6.8	4.9
Median	N/A	N/A	5.2	3.7
Q1	N/A	N/A	4.1	2.8
Minimum	N/A	N/A	0.1	0.2
Range	N/A	N/A	29.9	29.7
Mode	N/A	N/A	4.5	2.9
Percentiles
99%	N/A	N/A	16.5	13.8
95%	N/A	N/A	11.1	8.4
90%	N/A	N/A	9.0	6.7
10%	N/A	N/A	3.3	2.2
5%	N/A	N/A	2.8	2.0
1%	N/A	N/A	1.9	1.5
Extremes
5 Highest Values
(Highest)	N/A	N/A	30.0	29.8
	N/A	N/A	29.9	29.5
	N/A	N/A	29.8	29.3
	N/A	N/A	29.3	29.3
	N/A	N/A	29.2	29.3
5 Lowest Values
	N/A	N/A	0.1	0.2
	N/A	N/A	0.1	0.2
	N/A	N/A	0.1	0.2
	N/A	N/A	0.1	0.2
(Lowest)	N/A	N/A	0.1	0.2
Note: Time recording begins at screen LEADSEN in the Social Environment Module and stops recording after screen SEN13D in the Social Environment Module.

Table 6.21 2000 NHSDA Timing Data: Parenting Experiences Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	N/A	N/A	41,324	46,033
Summary Statistics (in Minutes)
Mean ()	N/A	N/A	0.2	0.2
Variance (2)	N/A	N/A	0.6	0.7
Standard Deviation ()	N/A	N/A	0.8	0.9
Quartiles
Maximum	N/A	N/A	29.3	23.5
Q3	N/A	N/A	0.0	0.0
Median	N/A	N/A	0.0	0.0
Q1	N/A	N/A	0.0	0.0
Minimum	N/A	N/A	0.0	0.0
Range	N/A	N/A	29.3	23.5
Mode	N/A	N/A	0.0	0.0
Percentiles
99%	N/A	N/A	3.4	3.9
95%	N/A	N/A	1.8	1.9
90%	N/A	N/A	0.0	0.0
10%	N/A	N/A	0.0	0.0
5%	N/A	N/A	0.0	0.0
1%	N/A	N/A	0.0	0.0
Extremes
5 Highest Values
(Highest)	N/A	N/A	29.3	23.5
	N/A	N/A	26.3	22.4
	N/A	N/A	24.7	22.4
	N/A	N/A	23.3	20.3
	N/A	N/A	19.8	18.8
5 Lowest Values
	N/A	N/A	0.0	0.0
	N/A	N/A	0.0	0.0
	N/A	N/A	0.0	0.0
	N/A	N/A	0.0	0.0
(Lowest)	N/A	N/A	0.0	0.0
Note: Time recording begins at screen LEADPAR in the Parenting Experiences Module and stops recording after screen PEO5d in the Parenting Experiences Module.

Table 6.22 2000 NHSDA Timing Data: Youth Experiences Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	24,856	25,633	N/A	N/A
Summary Statistics (in Minutes)
Mean ()	12.1	7.4	N/A	N/A
Variance (2)	18.9	8.8	N/A	N/A
Standard Deviation ()	4.3	3.0	N/A	N/A
Quartiles
Maximum	30.0	29.9	N/A	N/A
Q3	14.2	8.8	N/A	N/A
Median	11.4	6.9	N/A	N/A
Q1	9.1	5.4	N/A	N/A
Minimum	0.1	0.4	N/A	N/A
Range	29.9	29.5	N/A	N/A
Mode	10.8	6.1	N/A	N/A
Percentiles
99%	26.0	17.3	N/A	N/A
95%	20.4	12.8	N/A	N/A
90%	17.7	11.1	N/A	N/A
10%	7.4	4.3	N/A	N/A
5%	6.4	3.8	N/A	N/A
1%	3.9	2.6	N/A	N/A
Extremes
5 Highest Values
(Highest)	30.0	29.9	N/A	N/A
	30.0	29.7	N/A	N/A
	29.9	29.6	N/A	N/A
	29.9	29.2	N/A	N/A
	29.9	29.1	N/A	N/A
5 Lowest Values
	0.4	0.6	N/A	N/A
	0.4	0.5	N/A	N/A
	0.3	0.5	N/A	N/A
	0.3	0.5	N/A	N/A
(Lowest)	0.1	0.4	N/A	N/A
Note: Time recording begins at screen LEADSEN in the Youth Experience Module and stops recording after screen YE44 in the Youth Experience Module.

Table 6.23 2000 NHSDA Timing Data: Adolescent Mental Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	N/A	25,611	N/A	N/A
Summary Statistics (in Minutes)
Mean ()	N/A	7.6	N/A	N/A
Variance (2)	N/A	12.0	N/A	N/A
Standard Deviation ()	N/A	3.5	N/A	N/A
Quartiles
Maximum	N/A	29.2	N/A	N/A
Q3	N/A	9.5	N/A	N/A
Median	N/A	7.2	N/A	N/A
Q1	N/A	5.3	N/A	N/A
Minimum	N/A	0.3	N/A	N/A
Range	N/A	28.9	N/A	N/A
Mode	N/A	5.6	N/A	N/A
Percentiles
99%	N/A	18.2	N/A	N/A
95%	N/A	13.9	N/A	N/A
90%	N/A	12.1	N/A	N/A
10%	N/A	3.8	N/A	N/A
5%	N/A	2.9	N/A	N/A
1%	N/A	1.1	N/A	N/A
Extremes
5 Highest Values
(Highest)	N/A	29.2	N/A	N/A
	N/A	29.2	N/A	N/A
	N/A	29.1	N/A	N/A
	N/A	28.9	N/A	N/A
	N/A	28.8	N/A	N/A
5 Lowest Values
	N/A	0.3	N/A	N/A
	N/A	0.3	N/A	N/A
	N/A	0.3	N/A	N/A
	N/A	0.3	N/A	N/A
(Lowest)	N/A	0.3	N/A	N/A
Note: Time recording begins at screen DPSINTRO in the Adolescent Mental Health Module and stops recording after screen DPS71 in the Adolescent Mental Health Module.

Table 6.24 2000 NHSDA Timing Data: Youth Mental Health Service Utilization Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	N/A	25,625	N/A	N/A
Summary Statistics (in Minutes)
Mean ()	N/A	1.9	N/A	N/A
Variance (2)	N/A	3.2	N/A	N/A
Standard Deviation ()	N/A	1.8	N/A	N/A
Quartiles
Maximum	N/A	30.0	N/A	N/A
Q3	N/A	2.2	N/A	N/A
Median	N/A	1.5	N/A	N/A
Q1	N/A	1.0	N/A	N/A
Minimum	N/A	0.1	N/A	N/A
Range	N/A	29.9	N/A	N/A
Mode	N/A	1.1	N/A	N/A
Percentiles
99%	N/A	9.2	N/A	N/A
95%	N/A	4.5	N/A	N/A
90%	N/A	3.4	N/A	N/A
10%	N/A	0.8	N/A	N/A
5%	N/A	0.6	N/A	N/A
1%	N/A	0.2	N/A	N/A
Extremes
5 Highest Values
(Highest)	N/A	30.0	N/A	N/A
	N/A	29.8	N/A	N/A
	N/A	29.7	N/A	N/A
	N/A	28.7	N/A	N/A
	N/A	28.4	N/A	N/A
5 Lowest Values
	N/A	0.1	N/A	N/A
	N/A	0.1	N/A	N/A
	N/A	0.1	N/A	N/A
	N/A	0.1	N/A	N/A
(Lowest)	N/A	0.1	N/A	N/A
Note: Time recording begins at screen INTROYSU in the Youth Mental Health Service Utilization Module and stops recording after screen YSU29 in the Youth Mental Health Service Utilization Module.

Table 6.25 2000 NHSDA Timing Data: Total Back-End FI Administered

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,067	25,441	41,002	45,602
Summary Statistics (in Minutes)
Mean ()	10.8	10.4	10.8	11.8
Variance (2)	22.7	24.7	21.1	25.2
Standard Deviation ()	4.8	5.0	4.6	5.0
Quartiles
Maximum	51.1	62.8	61.9	69.1
Q3	13.3	12.8	13.1	14.2
Median	10.1	9.5	10.1	11.0
Q1	7.4	6.9	7.6	8.4
Minimum	0.2	0.1	0.1	0.2
Range	50.8	62.7	61.7	68.9
Mode	9.4	6.8	9.2	9.3
Percentiles
99%	25.7	27.0	25.8	29.2
95%	19.4	19.6	19.2	21.1
90%	16.9	16.7	16.6	18.1
10%	5.5	5.2	5.8	6.6
5%	4.6	4.4	4.9	5.6
1%	3.2	3.2	3.2	3.9
Extremes
5 Highest Values
(Highest)	51.1	62.8	61.9	69.1
	51.0	56.6	49.9	59.1
	49.3	56.3	49.8	50.7
	48.1	53.2	46.3	48.9
	46.0	52.3	45.5	47.6
5 Lowest Values
	0.7	0.4	0.3	0.3
	0.5	0.4	0.2	0.3
	0.4	0.4	0.2	0.3
	0.2	0.3	0.1	0.3
(Lowest)	0.2	0.1	0.1	0.2
Note: Time recording begins at screen INTRODM2 in the Back-End Demograhics Module and stops recording after screen TOALLR3 in the Income Module.

Table 6.26 2000 NHSDA Timing Data: Back-End Demographics Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,236	25,553	41,180	45,745
Summary Statistics (in Minutes)
Mean ()	5.1	5.4	5.8	7.4
Variance (2)	5.9	10.0	7.0	12.4
Standard Deviation ()	2.4	3.2	2.7	3.5
Quartiles
Maximum	29.7	29.7	29.9	30.0
Q3	6.2	6.8	7.0	8.9
Median	4.6	4.6	5.4	6.8
Q1	3.4	3.3	4.1	5.1
Minimum	0.1	0.1	0.0	0.1
Range	29.6	29.6	29.9	29.9
Mode	3.8	3.3	4.9	6.6
Percentiles
99%	13.1	16.6	15.0	20.0
95%	9.4	11.4	10.5	13.7
90%	8.1	9.4	9.0	11.5
10%	2.6	2.5	3.1	3.7
5%	2.2	2.1	2.5	2.9
1%	1.5	1.6	1.6	1.9
Extremes
5 Highest Values
(Highest)	29.7	29.7	29.9	30.0
	29.6	29.7	29.5	30.0
	29.4	29.6	29.4	29.9
	29.0	29.5	29.3	29.8
	29.0	29.3	29.1	29.7
5 Lowest Values
	0.3	0.2	0.1	0.1
	0.2	0.2	0.1	0.1
	0.2	0.1	0.1	0.1
	0.2	0.1	0.1	0.1
(Lowest)	0.1	0.1	0.0	0.1
Note: Time recording begins at screen INTRODM2 in the Back-End Demograhics Module and stops recording after screen MBRSELCT in the Back-End Demograhics Module.

Table 6.27 2000 NHSDA Timing Data: Income Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	25,236	25,641	41,185	45,939
Summary Statistics (in Minutes)
Mean ()	3.2	2.9	2.9	2.8
Variance (2)	3.7	3.7	3.2	3.4
Standard Deviation ()	1.9	1.9	1.8	1.8
Quartiles
Maximum	28.3	29.2	29.0	29.8
Q3	4.1	3.7	3.7	3.4
Median	2.9	2.5	2.6	2.4
Q1	1.9	1.7	1.7	1.7
Minimum	0.0	0.0	0.0	0.1
Range	28.2	29.2	28.9	29.7
Mode	1.9	1.8	2.2	1.8
Percentiles
99%	9.5	9.5	8.9	9.3
95%	6.5	6.1	5.9	5.8
90%	5.5	5.0	5.0	4.7
10%	1.3	1.2	1.2	1.2
5%	1.0	1.0	1.0	1.0
1%	0.6	0.6	0.6	0.6
Extremes
5 Highest Values
(Highest)	28.3	29.2	29.0	29.8
	26.5	29.2	28.8	29.4
	26.5	29.0	28.4	29.3
	26.2	28.8	27.1	29.2
	24.5	28.4	26.7	28.9
5 Lowest Values
	0.1	0.1	0.0	0.1
	0.1	0.1	0.0	0.1
	0.1	0.1	0.0	0.1
	0.0	0.1	0.0	0.1
(Lowest)	0.0	0.0	0.0	0.1
Note: Time recording begins at screen INTROINC in the Income Module and stops recording after screen TOALLR3 in the Income Module.

Table 6.28 2000 NHSDA Timing Data: FI Debriefing Section

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	24,977	25,496	40,783	45,648
Summary Statistics (in Minutes)
Mean ()	1.4	1.8	1.4	1.9
Variance (2)	3.6	4.1	3.9	5.2
Standard Deviation ()	1.9	2.0	2.0	2.3
Quartiles
Maximum	29.9	30.0	30.0	30.0
Q3	1.5	2.0	1.5	2.1
Median	0.9	1.3	0.9	1.3
Q1	0.6	0.8	0.6	0.9
Minimum	0.1	0.2	0.1	0.2
Range	29.8	29.7	29.9	29.8
Mode	0.6	0.8	0.6	1.0
Percentiles
99%	9.0	10.3	9.9	12.8
95%	3.6	4.4	3.8	5.1
90%	2.5	3.2	2.6	3.4
10%	0.4	0.6	0.4	0.6
5%	0.3	0.5	0.3	0.5
1%	0.2	0.4	0.2	0.4
Extremes
5 Highest Values
(Highest)	29.9	30.0	30.0	30.0
	29.8	29.7	30.0	30.0
	29.6	29.5	30.0	29.8
	29.6	29.0	29.5	29.7
	29.6	28.9	29.5	29.7
5 Lowest Values
	0.1	0.2	0.1	0.2
	0.1	0.2	0.1	0.2
	0.1	0.2	0.1	0.2
	0.1	0.2	0.1	0.2
(Lowest)	0.1	0.2	0.1	0.2
Note: Time recording begins at screen FIDBRINTR in the FI Debriefing Module and stops recording after screen FIEXIT in the FI Debriefing Module.

Table 6.29 2000 NHSDA Timing Data: 15 & Older Back-End Demographics 2: Employed vs. Unemployed

Age Category	12-17		18+
Year of Interest	1999	2000	1999	2000
Sample Size	35,013	6,114	38,560	7,146
Summary Statistics (in Minutes)
Mean ()	6.1	4.5	7.9	4.4
Variance (2)	6.9	5.7	11.2	7.7
Standard Deviation ()	2.6	2.4	3.4	2.8
Quartiles
Maximum	29.9	29.3	30.0	29.7
Q3	7.2	5.4	9.3	5.1
Median	5.7	4.0	7.3	3.8
Q1	4.4	3.0	5.8	2.8
Minimum	0.5	0.5	0.9	0.6
Range	29.4	28.8	29.0	29.1
Mode	5.2	3.4	6.8	2.6
Percentiles
99%	15.1	13.9	20.4	15.5
95%	10.7	8.7	14.1	9.2
90%	9.2	7.2	11.9	7.1
10%	3.4	2.2	4.7	2.2
5%	2.8	1.8	4.0	1.8
1%	1.9	1.2	3.0	1.3
Extremes
5 Highest Values
(Highest)	29.9	29.3	30.0	29.7
	29.5	28.0	30.0	29.7
	29.4	22.8	29.9	29.5
	29.1	22.1	29.8	28.5
	28.9	22.1	29.7	27.6
5 Lowest Values
	0.9	0.8	1.3	0.7
	0.9	0.8	1.1	0.7
	0.9	0.7	1.1	0.7
	0.9	0.7	1.1	0.6
(Lowest)	0.5	0.5	0.9	0.6
Note: Time recording begins at screen INTRODM2 in the Back-End Demograhics Module and stops recording after screen MBRSELCT in the Back-End Demograhics Module. 1"Employed" refers to currently employed or employed in the past 12 months and "Unemployed" refers to not employed in the past 12 months.

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