Washington State Department of Health Center for Health Statistics December 19, 2013 If you haven’t registered for this GoToWebinar, use this link: JoinWebinar.com ; enter Webinar ID: Dial in using telephone # provided. Be sure to enter PIN when it shows on your screen.

Objectives & Agenda Objectives:  Alert users to what’s new in 2012  Orient users to package contents to maximize utility  Address data users questions Agenda:  Contents of Release  README highlights  Weighting  Helpful Data Checks  Q&A

Organization of Package File Description and Use BRFSS 2012 Contents File

2012 BRFSS “Contents” File  Contents_WA_BRFSS_2012_DataRelease  Data Folder: SAS, STATA, SPSS*  Washington Documentation Folder  CDC Documentation Folder  Other files available by request  [View of Contents File] * SPSS “Complex Samples” add on required to analyze BRFSS

2012 Dataset Vitals Differences from 2011 Pointers to critical guidelines BRFSS 2012 README File

 Dual-frame sample (land & cell)  Single “form” (one questionnaire*)  Raked weights (both LLCP and LAND)  N=15,312; 17% from cell (n=2,551)  Can aggregate with 2011  Cannot aggregate with or compare estimates to data from 2010 and earlier (official release)  Changes (since 2011) to some variables and methods.

2011 vs General  New data collection contractor  New formula for calculating response rates.  Transition to new call disposition codes (fully implemented in 2013)  Shift in inclusion criteria for cell respondents  Inclusion of a “dual correction factor” in the design weight  Both LLCP & LAND weights provided in 1 file

2011 vs – Percent cell  Percent of WA total sample devoted to statewide cell: 8%  Percent of WA total sample devoted to statewide cell: 17% Wireless Substitution, 2012: a/nhsr/nhsr070.pdf

2011 vs Eligibility  Cell phone sample’s inclusion criteria changed (and changing).  Of all phone calls on landline and cell phone, what percent of calls received on cell? To be eligible for interview, if called as part of cell sample & % of calls on cell 90% of calls on cell>0% -100% cell usage. (all elig.) 2012 includes both “Cell Only” and “Cell Mostly”. Cell sample respondents who ALSO had a landline telephone had a greater than zero probability of ALSO being selected as part of the landline sample DESIGN weight accounts for this with a “Dual Use Correction Factor”. This is embedded in the final weights.

Dual Use Correction Factor  A “dual use correction factor” (_DUALCORR) is embedded in the design weight.  Applied to records where a respondent had chance of being selected in both sample frames (people with land & cell phones; cell phone used for 90-99% of all calls received.)  “_DUALUSE” variable indicates which records have a weight that incorporates this factor.  See “What weight to use 2012” document for more info

2011 vs Eligibility 2011 – Private Residence2012 – Private Residence “Do you live in a private residence?”  if “No”, then ineligible. Stop interview. “Do you live in a private residence?”  if “No”, then follow up: “Do you live in college housing?”  If “Yes”, continue.  if “No”, then ineligible. Stop interview.

2012 Variable Name Changes

[Switch to View of “What Weight to Use” document] 2012 What Weight To Use File

What Weights to Use  CDC vs. WA DOH weights?  Different population file (Claritas vs. WA OFM)  WA DOH trimmed LLCP weights to 75 th percentile  7 cell records dropped after CDC produced weights  LAND vs. LLCP weights?  Usually LLCP; evaluate effect of cell if sub-state/sub- pop  If aggregating/comparing to 2011, may have to use LADN (if Qs not admnistered on 2011 cell)  QSTVER : Land = 10; Cell = 20

Aggregating Weights  Can aggregate yrs only if they use the same weighting technique:  2010 and previous use poststratification  2011 and after use raking  Adjust the weights when combining years: “Adjusted weight” = “original weight” x (“number of respondents this year”/”number of respondents in combined years”)  Example: If Year 1 has N = 5,000; Year 2 has N = 15,000. Total sample is 5,000+15,000 = 20,000 Multiply Year 1’s weights by (5,000 / 20,000 ) = 0.25 x weights Multiple Year 2’s weights by (15,000 / 20,000) = 0.75 x weights

Suggested Code  Be sure to include survey design variables for Strata and Cluster (_STSTR and _PSU)  Include NOMCAR option (SAS only) – not missing completely at random  Note that STATA insert “A” in front of underscores  See examples of SAS and STATA code in the “What Weight to Use 2012.docx”

Get to know your data – Always check unweighted frequencies of all variables in your analysis Is sample size in all response options large enough to analyze, or do you need to aggregate years? Histograms. (See Guidelines for Working with Small Numbers: mbers.pdf) mbers.pdf Do responses make sense? Do all response options have responses? Etc. If anything looks super crazy, contact BRFSS epidemiologist: Data Checks

Routine Checks  Decision to include/exclude DK/REF. Set to missing or not? Check: Are DK & REF coded as “7” and “9” in your question? Is there an “8”?  Expected population included in numerator and denominator? Verify skip patterns in qrre.  Frequencies / counts in each response option  Check: Age sums? Which age variable using?

Users Data Checks Revealed…  Problem with colon cancer screening misclassification.  Differences in age variables (difference was intentional, but user was not aware of the difference.)  Assumptions behind calculated variables.  Change in measures used to calculate physical activity indicators.

Xtra Demographics in WA Data  Age Category asked if Age = DK/REF (varname)  Income: $75K - <$100K; $100K+  Marital Status: “Registered in a Domestic Partnership”  Type of Health Insurance  Industry & Occupation codes  Sexual Orientation

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Extra slides

Types of weights  The weight you use depends on your analysis question  Individual, respondent-level weights  WA and CDC  e.g. How many WA residents over age 18 have dental insurance?  Most commonly used weights  Child weights  WA and CDC  e.g. How many children in WA have asthma?  Sample sizes are small, so will likely need to aggregate years of data to get adequate N  Household weights  CDC only  e.g. How many households are there in WA in which a child has asthma?  Only can ask these questions of a module/question asks about more than just the respondent (asks about other adults, or about children)

LL vs LLCP weights  Cell phone sample is increasing toward the level of actual cell users in WA  Use LLCP weights whenever possible  LL: sample size = 12,761  LL Children: Sample size = 2,799  LLCP: sample size = 15,312  LLCP Children: Sample size = 3,532

Names of weights to use in analysis  Adult LL weights:  CDC: _LANDWT  WA: WALLWT  Adult LLCP weights:  CDC: _LLCPWT  WA: WALLCPWT  Child LL weights:  CDC: _CLANDWT  WA: WALLWTC  Child LLCP weights:  CDC: _CLLCPWT  WA: WALLCPWT_CH See Codebk12 and What Weight to Use 2012 documents for more info

Dual use correction  Dual users: individuals who had both cellular telephones and landline phones but mostly used cellular telephones  Design weight was multiplied by this a dual- use correction factor to generate a composite weight, which is used as the raking input weight to account for the overlapping sample frame  See “What weight to use 2012” document for more info