1. Introduction to IPUMS NYTS and IPUMS YRBSS

2. Introduction to IPUMS
Data overview
Harmonization
IPUMS NYTS
IPUMS YRBSS
Accessing data

3. What is IPUMS?
IPUMS integrates census and survey data collections across time and space. Harmonized variable codes and documentation make it easy to study change over time, pool data, and conduct comparative research. Data and services are available free of charge.

4. IPUMS NYTS and YRBSS
IPUMS NYTS and IPUMS YRBSS were produced with funding from the Food and Drug Administration (FDA) Center for Tobacco Products. Funding did not include support for dissemination, so data are not provided through the usual IPUMS data access system. These projects were a collaboration between NORC and IPUMS.

5. Introduction to IPUMS
Data overview
Harmonization
IPUMS NYTS
IPUMS YRBSS
Accessing data

6. Microdata
Microdata are composed of individual records containing information collected on persons (or other unit of analysis)
The responses of each person to the different questionnaire items are stored in separate variables
In contrast, summary or aggregate data are compiled statistics for a pre-selected subgroup or area. Microdata allow researchers the flexibility to generate the specific statistics or tabulations that suit their own research

7. Example microdata records for 4 individuals
Person Number
Marital status
Education
Occupation
Person 1
Person 2
Person 3
Person 4

8. Introduction to IPUMS
Data overview
Harmonization
IPUMS NYTS
IPUMS YRBSS
Accessing data

9. What is harmonization?
Combining datasets collected at different times into a single, consistent data series
Applying a coding scheme that connotes broadly comparable categories while retaining additional detail available in only a subset of years
Documenting details about the harmonization process and any potential comparability issues

10. Example of harmonization
Changes to race/ethnicity response categories in YRBSS
Pre-1999 Categories
1999-forward Categories
Native American or Alaska Native
Asian or Pacific Islander
Non-Hispanic Black
Non-Hispanic White
Hispanic/Latino
Other
Native American or Alaska Native
Asian
Native Hawaiian or other Pacific Islander
Non-Hispanic Black
Hispanic/Latino
Non-Hispanic White
Other

11. Example of harmonization (cont.)
Harmonization creates comparability between codes in pre-1999 and 1999-forward without losing detail from more recent years.
Pre-1999 categories with simple codes
Harmonized codes
1 = American Indian or Alaska Native 2 = Asian or Pacific Islander 3 = Non-Hispanic Black 4 = Non-Hispanic White 5 = Hispanic/Latino 6 = Other
10 = American Indian or Alaska Native
20 = Asian or Pacific Islander
21 = Asian
22 = Native Hawaiian or other Pacific Islander
30 = Non-Hispanic Black
40 = Non-Hispanic White
50 = Hispanic/Latino
60 = Other

12. Example of harmonization (cont.)
10 = American Indian or Alaska Native 20 = Asian or Pacific Islander 21 = Asian 22 = Native Hawaiian or other Pacific Islander 30 = NH Black 40 = NH White 50 = Hispanic/Latino 60 = Other
The first digit of the code is consistent across all years
The second digit of the code contains detail specific to 1999-forward

13. Example of harmonization (cont.)
Variable documentation in the codebook includes codes and labels, notes changes to response categories, and provides additional information about changes to the variable over time, including:
the option to report multiple races beginning in 1999,
the elimination of the “Hispanic/Latino” as a race category in 2005,
how ethnicity information is derived for this variable

14. Introduction to IPUMS
Data overview
Harmonization
IPUMS NYTS
IPUMS YRBSS
Accessing data

15. About NYTS National Youth Tobacco Survey (NYTS)
Cross-sectional nationally representative survey of youth grades 6-12
Fielded roughly biannually since 1999
On average, file includes over 20,000 youth each year it is fielded
Focuses on youth behavior, attitudes, and exposure to tobacco

16. IPUMS NYTS
Original public use data variable names reflect question number; IPUMS NYTS renames variables so they are consistent over time and reflect what the variable measures
Codes are harmonized to increase comparability without losing year-specific detail in the original files
IPUMS NYTS includes 10 years of available microdata from
Researchers using IPUMS NYTS microdata should use the following citation:
Matthew Sobek and Kari C.W. Williams. IPUMS National Youth Tobacco Survey [dataset]. Minneapolis, MN: IPUMS and Chicago, IL: NORC,

17. Introduction to IPUMS
Data overview
Harmonization
IPUMS NYTS
IPUMS YRBSS
Accessing data

18. About YRBSS Youth Risk Behavior Surveillance System (YRBSS)
Cross-sectional nationally representative survey of youth grades 9-12
Fielded biannually since 1991
On average, file includes over 14,000 youth each year it is fielded
Focuses on health risk behaviors developed during adolescence

19. IPUMS YRBSS
Original public use data variable names reflect question number; IPUMS YRBSS renames variables so they are consistent over time and reflect what the variable measures
Codes are harmonized to increase comparability without losing year-specific detail in the original files
IPUMS YRBSS includes 12 years of available microdata from
Researchers using IPUMS YRBSS microdata should use the following citation:
Daniel J. Backman, Greg Freedman Ellis, Matthew Sobek and Kari C.W. Williams. IPUMS Youth Risk Behavior Surveillance System [dataset]. Minneapolis, MN: IPUMS and Chicago, IL: NORC,

20. Introduction to IPUMS
Data overview
Harmonization
IPUMS NYTS
IPUMS YRBSS
Accessing data

21. Available Files
Zipped, fixed-width ASCII data file that contains harmonized variables and all years of data.
Syntax command files to read fixed width data into:
Stata
SAS
SPSS R
Codebook that includes detailed variable descriptions, codes, variable availability over time, and any notes on comparability issues for using the variable over time
Zipped directory containing original questionnaires
Technical assistance memo
Practical weight guidance memo

22. Unzipping and accessing data
IPUMS NYTS and YRBSS data are provided as a single raw ASCII file.
To analyze data, users must first download the data and syntax command file for their statistics package of choice.
IPUMS datasets are compressed; users must unzip the data file before using it.
Additional resources on decompression applications and tips for ensuring your statistical package can identify the correct working directory and data file are available under the “User Support” section of the IPUMS NYTS and IPUMS YRBSS sites.
Data users should reference the codebook for variable names and important information on comparability.
Users should review the technical assistance and practical weight guidance memos to ensure they fully understand how to weight analyses appropriately.