Medicaid Underreporting in the CPS: Results from a Record Check Study Joanne Pascale Marc Roemer Dean Resnick US Census Bureau DCAAPOR August 21, 2007

2 Medicaid Undercount Records show higher Medicaid enrollment levels than survey estimates (~10-30%) Undercount affects many different surveys of health insurance Non-reporting error sources contribute Under-reporting is the largest contributor to the undercount

3 Current Population Survey Focus is on under-reporting in CPS –Produces most widely-cited estimates on health insurance and uninsured –Other surveys gauge estimates against CPS; mimic CPS design CPS = monthly survey on labor force and poverty; health insurance questions asked in annual supplement

4 CPS Health Insurance Questions: ‘Type by Type’ Structure 1.Job-based 2.Directly-purchased 3.Someone outside HH 4.Medicare 5.Medicaid 6.SCHIP 7.Military 8.Other

5 CPS Health Insurance Questions: Calendar Year Reference Period Survey is conducted in March Questions ask about coverage during previous calendar year “At any time during 2000, was anyone in this household covered by [plan type]?”

6 CPS Health Insurance Questions: Household-level Design Multi-person household: At anytime during 2000 was anyone in this household covered by [plan type]? [if yes] Who was that? Single-person household: At any time during 2000 were you covered by [plan type]?

7 CPS Cognitive Testing Three main sources of misreporting: 1.Type-by-type structure: Rs ‘pre-report’ and try to ‘fit’ coverage in earliest question 2.12-month reference period: some respondents focus on current coverage or ‘spell’ 3.Household size and complexity

8 More on HH Size and Complexity Rs forgot about certain HH members Rs did not know enough detail about other HH members’ plan type Neither problem related to ‘closeness’ between R and referent; affected housemates, distant relatives but also parents, siblings, live-in partners

9 Shared Coverage Hypothesis Health insurance administered in ‘units’ –Private and military coverage: nuclear family –Medicaid and ~SCHIP: parent and children –Medicare: individual Any given HH may have a mix of units E.g.: R on his union plan; mother on Medicare; sister and child on Medicaid; live-in partner and her child on her job plan R may be able to report more accurately for HH members who are in their same unit (i.e.: share the same coverage type)

10 Methods Linked CPS survey and ‘MSIS’ record data for year 2000 Analysis Dataset: CPS sample members… –known to be on Medicaid according to records –for whom a direct response to ‘Medicaid’ was reported in CPS (not edited or imputed) Several items fed into ‘Medicaid’ indicator (Medicaid, SCHIP, other government plan, other) –n = 19,345 Dependent var = whether Medicaid was reported for the known enrollees

11 Shared Coverage Variable Referent (person reported on) is R (self-report) A.in single-person hh B.in multi-person hh Referent is not R (proxy report) C.But both are on same Medicaid case D.But both are on Medicaid (different cases) E.Referent is on Medicaid; R is not

12 Logistic Regression Model Dependent var = Medicaid status reported in CPS Independent vars: HH composition –Shared coverage var –Another HH member had Medicaid w/in year Recency and intensity of coverage –Most recent month referent enrolled –Proportion of days covered from January till last month enrolled –Referent covered in survey month Referent received Medicaid services w/in year Demographics –Sex of R –Age and race/ethnicity of referent

13 Results: Overview of Linked Dataset Of 173,967 CPS hh members, 19,345 (11.1%) had Medicaid according to records Medicaid was reported in CPS for only 12,351 (7.1%) hh members => 36.2% under-reporting

14 Results: Overall Regression Model is highly significant in explaining misreporting Effect of each variable is significant and highly discernible Ranked each of the 9 independent vars according to its importance to model

15 Ranking of Independent Vars 1.Most recent month enrolled 2.Proportion of days covered from January 3.Received Medicaid services w/in year 4.Race/ethnicity of referent 5.Sex of respondent 6.Another HH member had coverage w/in year 7.Age of referent 8.Covered in survey month 9.Shared coverage var

16 Categorization of Independent Vars Recency and intensity of coverage 1.Most recent month enrolled 2.Proportion of days covered from January till last month enrolled 8.Covered in survey month Receipt of Medicaid services 3.Received services with/in year Demographics 4.Race/ethnicity of referent (white non-Hispanic) 5.Sex of R 7.Age of referent HH composition 6.Another HH member had coverage w/in year 9.Shared coverage var

17 Results: Shared Coverage Var Expected ranking: A: Self report in single-person HH B. Self report in multi-person HH C. Proxy report, same case D. Proxy report, different case E. Proxy report; R does not have Medicaid Actual ranking: A C D/B E

18 Summary Recency, intensity of coverage Receipt of Medicaid services Shared coverage  All contribute to the saliency of Medicaid to the respondent, which could translate to more accurate reporting Rs in multi-person HHs forget to report their own coverage

19 Conclusions 1. Key components of wording are problematic: “At any time during calendar year…” “…was anyone in this household covered…”  Explore questionnaire design alternatives  2. Reporting accuracy goes up if R and referent both have Medicaid  Explore questionnaire designs to exploit this  See if results apply to other coverage types

20 Thoughts on Next Steps 1.Reference period: start with questions about current status ask when that coverage began ‘walk’ back in time to beginning of calendar year 2. Other hh members and shared coverage: Start with R’s coverage For each plan type reported ask if other hh members are also covered Continue asking about other hh members by name

21 THANK YOU!!

22 Finding low-income telephone households and people who do not have health insurance using auxiliary sample frame information for a random digit dial survey Tim Triplett, The Urban Institute David Dutwin, ICR Sharon Long, The Urban Institute DCAPPOR Seminar August 21, 2007

23 Presentation Overview Purpose: Obtain representative samples of adults without health insurance and adults in low (less than 300 percent of the federal poverty level (FPL)) and medium (between 300 and 500 percent FPL) income families while still being able to produce reliable estimates for the overall population. Strategy: Telephone exchanges within Massachusetts were sorted in descending order by concentration of estimated household income. These exchanges were divided into three strata and we oversampled the low and middle income strata. Results: Oversampling of low and medium income strata did increase the number of interviews completed with adults without health insurance as well as adults living at or below 300 percent FPL.

24 About the Study Telephone survey conducted in Massachusetts Collect baseline data prior to implementation of the Massachusetts universal health care coverage plan Started on October 16, 2006, ended on January 7, ,010 interviews with adults 18 to 64 Key sub groups were low and middle income households and uninsured adults Overall response rate 49% (AAPOR rr3 formula)

25 Sample design features RDD list +2 exchanges stratified by income and group into high, middle, and low income strata Over-sampled the low-income strata (n=1381) Separate screening sample was used to increase sample of uninsured (n=704) More aggressive over-sampling of the low income strata on the screening sample One adult interviewed per household Household with both insured and uninsured adults the uninsured adults had a higher chance of selection No cell phone exchanges were sampled

Percentage of uninsured and low-income adults by income strata

27 Alternate sampling strategies that could yield enough uninsured respondents without increasing survey costs None – no oversampling of strata – simply increase the amount of screening interviewers OS (2:2:1, 3:2:1) - release twice as much sample in the main study from the low and middle income strata and 3 times as much in the screener survey OS *(3:2:1, 5:3:1) - strategy we used OS (5:3:1, 5:3:1) - same for main and screener OS (5,3:1, 8:4:1) – heavy oversample in screener

Simulation of sample sizes resulting from the various oversampling strategies

29 Why not go for the largest sample Design effects will increase as the sample becomes more clustered Larger design effects means smaller effective sample sizes So comparing different sampling strategies you need to compare effective sample sizes We can only calculate the design effect (and effective sample size) for the sample strategy we employed Isolating the increase in the design effect due to the oversampling allows us to estimate the design effect for the other strategies

Average Design Effects

Simulation of effective sample sizes under various oversampling rules taking into consideration design effects

32 Conclusions Oversampling using exchange level information worked well Higher oversampling rate for the screener sample may not have been the best strategy Exchanges still cluster enough to use auxiliary information Except for the design we used – these are simulated estimates

33 Sampling in the next round Consider increasing (slightly) the oversampling rate for the main sample and decreasing (slightly) the rate for the screener sample or use the same rate Need to sample cell phone exchanges Health Insurance coverage likely to be higher Conduct Portuguese interviews

34 Thank You The survey was funded by the Blue Cross Blue Shield Foundation of Massachusetts, The Commonwealth Fund, and the Robert Wood Johnson Foundation. The analysis of the survey design was funded by the Urban Institute’s Statistical Methods Group.

Switching From Retrospective to Current Year Data Collection in the Medical Expenditure Panel Survey-Insurance Component (MEPS-IC) Anne T. Kearney U.S. Census Bureau John P. Sommers Agency for Healthcare Research and Quality

36 Important Terms Retrospective Design: collects data for the year prior to the collection period Current Year Design: collects data in effect at the time of collection Survey Year: the year of data being collected in the field Single Unit Establishment vs. Multi-Unit Establishment

37 Outline Background on MEPS-IC Why Switch to Current?/Barriers to Switching Impact on Frame and Reweighting Methodology Details of Current Year Trial Methods Results Summary

38 Background on MEPS-IC General Annual establishment survey that provides estimates of insurance availability and costs Sample of 42,000 private establishments National and state-level estimates Retrospective design

39 Background on MEPS-IC Timing Example Let’s say retrospective design in survey year 2002 –Create frame/sample in March 2003 using 2001 data from the business register (BR) –Create SU birth frame with 2002 data from BR –In the field from roughly July-December 2003 –Reweighting in March-April 2004 using 2002 data from the BR –Estimation and publication in May-June 2004

40 Why Switch to a Current Year Design? Estimates published about 1 year sooner Some establishments report current data already; current data is at their fingertips Most survey estimates are conducive to current year design Better coverage of businesses that closed after the survey year and before the field operation Some data users in favor of going current

41 Barriers to Switching to a Current Year Design One year older data for frame building One year older data for reweighting These could possibly make our estimates very different which we believe means worse Other data users believe retrospective design is better for collecting certain items

42 Impact on Frame Example:Let’s use 2002 survey year again: RetrospectiveCurrent Year Create Frame inMarch 2003March 2002 SU data available2001 MU data available Pick up SU Births?Yes, 2002No Drop SU Deaths?Yes, 2002No

43 Impact on Reweighting Nonresponse Adjustment We use an iterative raking procedure We do the NR Adjustment using 3 sets of cells: – Sector Groups – SU/MU – State by Size Group

44 We use an iterative raking procedure using 2 sets of cells: – State by Size Group and SU/MU Under the retrospective design for the 2002 survey: Impact on Reweighting Poststratification

45 Details of Trial Methods One issue for frame: –What to do with the births One issue for nonresponse adjustment: –What employment data to use for cell assignments Three issues for poststratification: –What employment data to use for cell assignments –What employment data to use for total employment –What payroll data to use to create the list of establishments for total employment

46 Details of Trial Methods 2002 Survey Method #Employment Data for Cells/Poststrat Totals Inscope List ID’d Using Data from.. Drop Births from Sample? SUMUSUMUSUMU Production 2002 No No No No YesNo Yes

47 Details of Trial Methods 2002 Survey Method #Employment Data for Cells/Poststrat Totals Inscope List ID’d Using Data from.. Drop Births from Sample? SUMUSUMUSUMU Production 2002 No No No No YesNo Yes

48 Details of Trial Methods 2002 Survey Method #Employment Data for Cells/Poststrat Totals Inscope List ID’d Using Data from.. Drop Births from Sample? SUMUSUMUSUMU Production 2002 No No No No YesNo Yes

49 Details of Trial Methods 2002 Survey Method #Employment Data for Cells/Poststrat Totals Inscope List ID’d Using Data from.. Drop Births from Sample? SUMUSUMUSUMU Production 2002 No No No No YesNo Yes

50 Details of Trial Methods 2002 Survey Method #Employment Data for Cells/Poststrat Totals Inscope List ID’d Using Data from.. Drop Births from Sample? SUMUSUMUSUMU Production 2002 No No No No YesNo Yes

51 Results Definitions National level estimates Estimates by firm size –Establishments categorized by their firm employment SizeNumber of Employees Large1000+ Medium50 – 999 Small1 - 49

52 Results Survey Year 2002 Estimate: % Estabs that offer insurance Prod Trial Method (Method minus Prod) 1235 Natl *1.07*0.80*0.45* L Firm M Firm S Firm *0.67*0.41*0.57* * Indicates significant difference

53 Results Survey Year 2003 Estimate: % Estabs that offer insurance Prod Trial Method (Method minus Prod) 35 Natl *-0.11 L Firm M Firm S Firm *0.01 * Indicates significant difference

54 Results Survey Year 2004 Estimate: % Estabs that offer insurance Prod Trial Method (Method minus Prod) 35 Natl *0.32 L Firm M Firm S Firm *0.75* * Indicates significant difference

55 Results Survey Year 2005 Estimate: % Estabs that offer insurance Prod Trial Method (Method minus Prod) 35 Natl * L Firm * M Firm S Firm *-0.57* * Indicates significant difference

56 Results Survey Year 2002 Estimate: Avg. Single Premium Prod Trial Method (Method minus Prod) 1235 Natl $3,191-$5*-$3-$1-$4 L Firm $3,136-$1$1 -$7 M Firm $3,134$2-$4-$2-$6 S Firm $3,374-$25*-$9*-$4$4 * Indicates significant difference

57 Results Survey Year 2003 Estimate: Avg. Single Premium Prod Trial Method (Method minus Prod) 35 Natl $3,483$2$8 * L Firm $3,428$17* M Firm $3,458-$10$0 S Firm $3,620-$5$7 * Indicates significant difference

58 Results Survey Year 2004 Estimate: Avg. Single Premium Prod Trial Method (Method minus Prod) 35 Natl $3,707-$1$1 L Firm $3,682-$3-$8 M Firm $3,713$5$11 S Firm $3,748-$1$10 * Indicates significant difference

59 Results Survey Year 2005 Estimate: Avg. Single Premium Prod Trial Method (Method minus Prod) 35 Natl $3,992$1$3 L Firm $3,933$7$2 M Firm $3,972$14$18 S Firm $4,134-$24-$14 * Indicates significant difference

60 Governments Sample Need Survey Year Data For the Governments Sample, we need to wait until survey year data is available: –we don’t collect employment from government units to use for our published employment estimates – we use data from the governments frame

61 Summary Many positives with going current – timing Possible frame and reweighting problems but prior year data are a good substitute Tested 4 Trial Methods and found: –Estimates of premiums look good and rates looked reasonable –Establishment and employment estimates are different but not most important estimates

62 Summary (cont.) We are planning to switch to a current year design for survey year 2008 using a methodology similar to Method 5. For the Governments Sample, we need to wait until survey year data is available: – we don’t collect government unit employment to use for employment totals

63

DC-AAPOR Discussant Notes AAPOR/ICES Encore: Issues in Health Insurance David Kashihara Agency for Healthcare Research and Quality (AHRQ) August 21, 2007

65 Issues in Health Insurance Topic is at the forefront of American consciousness Surveys of health are vital to both policy- makers and researchers Improving these surveys should result in better policies and improved research

66 Medicaid Under-reporting Pascale, Roemer & Resnick The Problem: –Significant amount of Medicaid misreporting 36.2% in the linked data set –Undercount probably present in other surveys

67 Medicaid Under-reporting Pascale, Roemer & Resnick Linking CPS records to MSIS: –Truth: MSIS records –Non-Truths? MSIS “no” but CPS “yes” (over-reports) Non-matching records (multiple state claims) Duplicates – were removed in this study How many? Impact?

68 Medicaid Under-reporting Pascale, Roemer & Resnick The Solution Good use of survey methodology –Cognitive testing –Methods –Analysis Confirmed the logical –Recency, intensity: salience plays big part Found the not-so-logical –R’s in multi-psn HH’s sometimes forget to report own coverage

69 Medicaid Under-reporting Pascale, Roemer & Resnick Question: –If the MSIS is the Truth, how good is the truth? Important result: –Findings can hopefully help other surveys of health identify, reduce or adjust for this misreporting

70 Low Income, No Insurance HH’s Triplett, Dutwin & Long Lack of health insurance in U.S. a hot topic –13.7 % of U.S., non-institutionalized, < 65 (MEPS, 2004) Low income & no insurance are related

71 Low Income, No Insurance HH’s Triplett, Dutwin & Long Medical Expenditure Panel Survey (MEPS) –U.S., non-institutionalized, < 65 population –% of persons lacking health insurance: Jan. – Dec by income level Income Level % of FPL % Psns (s.e.) Poor< (0.75) Low125 – < (1.05) Middle200 – < (0.60) High (0.42)

72 Low Income, No Insurance HH’s Triplett, Dutwin & Long More info about stratification of exchanges based on income –What was used to determine income level? –How accurate is this? –Are the clusters homogenous? (yes) No cell phone exchanges sampled –Cell only population –Increase or decrease # of uninsured? My guess: increase # uninsured ages18-24 years highest uninsured group < 65 years (22.5 %)

73 Low Income, No Insurance HH’s Triplett, Dutwin & Long Good use of design effects –Measure provides info not always intuitive to the untrained population –Some may always assume that more oversampling is better –Let statistics work for you

74 Low Income, No Insurance HH’s Triplett, Dutwin & Long If possible, try other factors that affect insurance coverage –Age –Race/Ethnicity

75 Low Income, No Insurance HH’s Triplett, Dutwin & Long Medical Expenditure Panel Survey (MEPS) –U.S., non-institutionalized, < 65 population –% of persons lacking health insurance: Jan. – Dec by age group Age Group % Psns No Ins (s.e.) < 186.8(0.44) (1.03) 25 – (0.63) 45 – (0.53)

76 Low Income, No Insurance HH’s Triplett, Dutwin & Long Medical Expenditure Panel Survey (MEPS) –U.S., non-institutionalized, < 65 population –% of persons lacking health insurance: Jan. – Dec by race/ethnicity Race/ Ethnicity % Psns No Ins (s.e.) Hispanic28.1(0.94) Black, Non- Hisp. 15.0(1.09) Asian/Ot h, Non- Hisp. 10.3(0.38)

77 Retrospective to Current Year Design Kearney & Sommers Decisions, Decisions, Decisions –How close is good enough? –Weighted pros & cons list –Administrative barriers

78 Retrospective to Current Year Design Kearney & Sommers Good list of pros & cons On the balance: –Different data users prefer different designs –Best design to please the most data users? –Best design for accurate estimates? –What is most important? What the users want

79 Retrospective to Current Year Design Kearney & Sommers How good is the Gold Standard (GS)? –“Survey-Year Data” –Reason it’s a GS –GS may have flaws –Sometimes methodology changes correct or cancel biases –GS is nice to have, but many surveys don’t have this luxury and still produce excellent estimates

80 Retrospective to Current Year Design Kearney & Sommers Well devised study –Trials useful to tease out sources of problems –Results look promising – a convincing argument to move forward Impact of the “minor” estimates? –Found to be different

81 Retrospective to Current Year Design Kearney & Sommers Transition to new design – any contingency plans? –In case new design doesn’t work well in reality –Concurrent samples (old & new methods) Draw 2 nd sample (old method) when items become available –Estimate bias between methods –Not cost effective or efficient

82 Issues in Health Insurance Three very good studies Methods & findings could be applied to other surveys We should be constantly improving surveys & making them more useful