NLSCY – Elements to take into account

Objectives of the Presentation zEmphasize the key elements to consider of when using NLSCY data

Why to look at these elements? zNLSCY is a longitudinal survey with a complex sample design zAs a result, it has implications on the analysis to be done with the data

The elements z1 – Objectives of the study z2 – Data sources, domain of study z3 – Type of study z4 – Non response z5 - Use of the design weights z6 - Appropriate variance calculation z7 - Statistical tests and analytical methods

1 – Objectives of the study zWhat do you want to study? zWhat do you want to do with the data? yTo make inference about a population? yfor a case study? yTo identify findings, without making inference to a population? yFor comparison with other sources of data?

2 - Data sources zAre the data sources clearly identified? y Cycle(s) used? y Which subgroups or domains? yWhich variables are used? y NLSCY target population well defined?

2 - Data sources (cont’d) zAre the data sources clearly identified? yAre the NLSCY data limitations clearly identified? ySample sizes provided? Are the sample sizes sufficient? Confidentiality issues?

3 - Type of study z What type of study? y Longitudinal? y Cross-sectional y NLSCY used as a repeated survey? y Mix of the above? zReminder: The unit of analysis is the child.

4 – Partial non response (item non response) z Are the response rates stated for the key variables? zIs there a non response analysis being done to handle the non response?

4 – Partial non response (cont’d) z How is it handled? yImputation? yReweighting? yReported as a value? yIgnored, study based on the respondents only?

5 - Design weights z Are the design weights used? y Appropriate weights (cross-sectional, longitudinal) used? y Revised weights or the original weights? y Re-weighting done to account for the partial non-response? zIf the weights are not used, why?

6 - Variance z How is the variance calculated for all the estimates? y CV look-up tables? y Excel spreadsheet with CVs for proportions? y Using the Bootstrap weights? y Using a SAS or SPSS procedure, without taking into account the design? : a big DON’T. y No variance? Another big DON’T

6 – Variance – an aside z Other surveys are providing stratum and PSU identifiers to calculate the variance zNLSCY has a high percentage of strata with only one PSU. y study under way to determine the feasibility of providing stratum/PSU Ids.

7 - Statistical tests z Were statistical tests used? y If so, are they clearly identified? y Are they appropriate for what you are doing?

In brief zWould an other researcher be able to replicate your results, given you have used all the appropriate methods (weights, variance, statistical tests)?

Questions