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  • survey data - 90% CIs for a proportion - tabulate or proportion?

    HI all, I'm analyzing survey data. I have a series of proportions and would like to produce standard errors and 90% CIs around the proportions. I've accounted for the survey design and incorporated replicate weights. Due to the sample size, this analysis produces some categories with very small numbers of people. As others have pointed out, and supported by the below code, proportion and tabulate seem to be producing the same proportions and standard errors, but the 90% CIs differ. (Note: in the below code, the category subpop_7 in the proportion results should match the results from the tabulate command). My questions:

    1) I am leaning toward using the tabulate results for the CIs, as some of the CIs using the "proportion" option are negative. Thoughts?

    2) Are there other ways of calculating the 90% CIs in Stata for survey proportions that I should consider here?

    3) Are there any good applied research studies with good examples of how to present the proportions and SEs or 90% CIs? (tables or graphs) - maybe not a Stata question.

    thanks in advance for any advice!


    Code:
    
    . svyset [pw = WTSURVY], jkrw(RW0001- RW0320, multiplier(0.05)) vce(jack) mse
    
          pweight: WTSURVY
              VCE: jackknife
              MSE: on
        jkrweight: RW0001 .. RW0320
      Single unit: missing
         Strata 1: <one>
             SU 1: <observations>
            FPC 1: <zero>
    
    
    
    . svy: proportion RACETHM_n, over(career_stage_rev2 DGRDG_n) level(90)
    (running proportion on estimation sample)
    
    Jackknife replications (320)
    ----+--- 1 ---+--- 2 ---+--- 3 ---+--- 4 ---+--- 5 
    ..................................................    50
    ..................................................   100
    ..................................................   150
    ..................................................   200
    ..................................................   250
    ..................................................   300
    ....................
    
    Survey: Proportion estimation
    
    Number of strata =       1        Number of obs   =      1,311
                                      Population size = 252,142.35
                                      Replications    =        320
                                      Design df       =        319
    
       AsianNHOPI: RACETHM_n = AsianNHOPI
             AIAN: RACETHM_n = AIAN
            Black: RACETHM_n = Black
         Hispanic: RACETHM_n = Hispanic
            White: RACETHM_n = White
               MR: RACETHM_n = MR
    
             Over: career_stage_rev2 DGRDG_n
        _subpop_1: 20 or more years Bachelors
        _subpop_2: 20 or more years Masters
        _subpop_3: 20 or more years Doctorate
        _subpop_4: 20 or more years Professional
        _subpop_5: Less than 20 yrs Bachelors
        _subpop_6: Less than 20 yrs Masters
        _subpop_7: Less than 20 yrs Doctorate
        _subpop_8: Less than 20 yrs Professional
    
    --------------------------------------------------------------
                 |              Jknife *N             ormal
            Over | Proportion   Std. Err.     [90% Conf. Interval]
    -------------+------------------------------------------------
    AsianNHOPI   |
       _subpop_1 |   .0232649   .0103291      .0062255    .0403043
       _subpop_2 |   .0101458   .0081955     -.0033739    .0236655
       _subpop_3 |   .0861882   .0234436      .0475145    .1248618
       _subpop_4 |          0  (no observations)
       _subpop_5 |   .1010706    .025582      .0588694    .1432719
       _subpop_6 |   .1334251   .0323168      .0801139    .1867364
       _subpop_7 |   .2483284    .043813      .1760524    .3206043
       _subpop_8 |          0  (no observations)
    -------------+------------------------------------------------
    AIAN         |
       _subpop_1 |          0  (no observations)
       _subpop_2 |    .022717   .0171829     -.0056286    .0510626
       _subpop_3 |          0  (no observations)
       _subpop_4 |          0  (no observations)
       _subpop_5 |    .000104    .000122     -.0000973    .0003053
       _subpop_6 |   .0080136    .005543     -.0011304    .0171576
       _subpop_7 |          0  (no observations)
       _subpop_8 |          0  (no observations)
    -------------+------------------------------------------------
    Black        |
       _subpop_1 |   .0325514   .0203369     -.0009974    .0661001
       _subpop_2 |   .0865779   .0572381     -.0078446    .1810005
       _subpop_3 |   .0072528   .0054652     -.0017628    .0162684
       _subpop_4 |          0  (no observations)
       _subpop_5 |   .0464535   .0292895     -.0018638    .0947708
       _subpop_6 |   .0848761   .0471426      .0071076    .1626445
       _subpop_7 |   .0030085   .0018134       .000017        .006
       _subpop_8 |          0  (no observations)
    -------------+------------------------------------------------
    Hispanic     |
       _subpop_1 |   .0366649   .0248132     -.0042681    .0775978
       _subpop_2 |   .0493453   .0213093      .0141927     .084498
       _subpop_3 |   .0232171   .0143399     -.0004386    .0468728
       _subpop_4 |          0  (no observations)
       _subpop_5 |   .0834066   .0350203      .0256355    .1411777
       _subpop_6 |   .0727584   .0242182       .032807    .1127099
       _subpop_7 |   .0743311   .0250366      .0330296    .1156325
       _subpop_8 |   .2790089   .2699777     -.1663584    .7243761
    -------------+------------------------------------------------
    White        |
       _subpop_1 |   .8807481    .043279       .809353    .9521431
       _subpop_2 |   .8079233   .0656598       .699608    .9162386
       _subpop_3 |    .880132   .0284381      .8332192    .9270448
       _subpop_4 |          1          .             .           .
       _subpop_5 |   .7615289   .0511107      .6772145    .8458433
       _subpop_6 |   .6686341   .0495443      .5869037    .7503645
       _subpop_7 |   .6694451   .0474141      .5912287    .7476614
       _subpop_8 |   .2771716   .2752663     -.1769198     .731263
    -------------+------------------------------------------------
    MR           |
       _subpop_1 |   .0267708   .0221536     -.0097747    .0633164
       _subpop_2 |   .0232907   .0153762     -.0020746     .048656
       _subpop_3 |   .0032099   .0024432     -.0008206    .0072404
       _subpop_4 |          0  (no observations)
       _subpop_5 |   .0074364   .0028953      .0026601    .0122126
       _subpop_6 |   .0322927   .0186794      .0014783     .063107
       _subpop_7 |    .004887    .003178     -.0003555    .0101295
       _subpop_8 |   .4438195   .2456526      .0385802    .8490589
    --------------------------------------------------------------
    
    . 
    . svy, subpop(if career_stage_rev2==2 & DGRDG_n==3): tabulate RACETHM_n, se ci level(90)
    (running tabulate on estimation sample)
    
    Number of strata   =         1                  Number of obs     =      1,311
                                                    Population size   = 252,142.35
                                                    Subpop. no. obs   =        241
                                                    Subpop. size      =  43,459.37
                                                    Replications      =        320
                                                    Design df         =        319
    
    ----------------------------------------------------------
    RACETHM_n | proportion          se          lb          ub
    ----------+-----------------------------------------------
     AsianNHO |      .2483       .0438       .1832       .3273
         AIAN |          0           0                        
        Black |       .003       .0018       .0011       .0081
     Hispanic |      .0743        .025       .0422       .1277
        White |      .6694       .0474       .5872       .7425
           MR |      .0049       .0032       .0017       .0142
              | 
        Total |          1                                    
    ----------------------------------------------------------
      Key:  proportion  =  cell proportion
            se          =  jackknife standard error of cell proportion
            lb          =  lower 90% confidence bound for cell proportion
            ub          =  upper 90% confidence bound for cell proportion
    
      Table contains a zero in the marginals.
      Statistics cannot be computed.
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