**Table 5: Payment results for subsample with bills**

||**Full Sample**||**Bill Sample**||
|---|---|---|---|---|
||Pr(any payment)|Pr(any payment)|Proportion paid|Pr(fully paid)|
|**Pooled treatment arms**|||||
|Treated|0.0205<sup>_∗∗∗_</sup>|0.0223<sup>_∗∗∗_</sup>|0.0197<sup>_∗∗∗_</sup>|0.0166<sup>_∗∗∗_</sup>|
||(0.00229)|(0.00486)|(0.00440)|(0.00418)|
|**Separate treatment arms**|||||
|T1: Reminder|0.0199<sup>_∗∗∗_</sup>|0.0224<sup>_∗∗∗_</sup>|0.0190<sup>_∗∗∗_</sup>|0.0159<sup>_∗∗∗_</sup>|
||(0.00256)|(0.00545)|(0.00492)|(0.00468)|
|T2: Reciprocity|0.0232<sup>_∗∗∗_</sup>|0.0241<sup>_∗∗∗_</sup>|0.0224<sup>_∗∗∗_</sup>|0.0201<sup>_∗∗∗_</sup>|
||(0.00283)|(0.00600)|(0.00545)|(0.00519)|
|T3: Social pressure|0.0167<sup>_∗∗∗_</sup>|0.0185<sup>_∗∗_</sup>|0.0162<sup>_∗∗_</sup>|0.0111<sup>+</sup>|
||(0.00317)|(0.00676)|(0.00610)|(0.00578)|
|Control mean|0.109|0.109|0.095|0.078|
|First stage f-stat|135,432|28,065.7|28,065.7|28,065.7|
|R<sup>2</sup>|0.001|0.001|0.001|0.001|
|Obs|143,425|31,554|31,554|31,554|
|Test: T1 = T2|0.210|0.752|0.498|0.383|
|Test: T1 = T3|0.254|0.518|0.596|0.349|
|Test: T2 = T3|0.047|0.418|0.317|0.132|

**Notes:** Table shows results for payment outcomes for both entire experimental sample and the subsample for which we have bill data. The outcomes in columns (1) and(2) is an indicator equal to one if the taxpayer has made any paymen to the TRA during the study period. The outcome in column (3) is the share of the total cumulative tax bill the taxpayer made by the end of the study period. The outcome in column (4) is an indicator equal to one if the taxpayer has fully paid their tax bill by the end of the study period. All results are 2SLS results where the actual messages sent to the taxpayer are instrumented using the original treatment assignment. Robust standard-errors in parentheses.<sup>+</sup> _p <_ 0 _._ 10 _,_<sup>_∗_</sup> _p <_ 0 _._ 05 _,_<sup>_∗∗_</sup> _p <_ 0 _._ 01 _,_<sup>_∗∗∗_</sup> _p <_ 0 _._ 001

For this analysis, we drop sub-wards with fewer than 100 observations (roughly 4 percent of the total experimental sample), leaving us with 360 sub-wards. For each sub-ward, we run our standard regressions, where the outcome is an indicator equal to one if the taxpayer made any payment to the TRA during the study period as a function of the reduced form treatment assignment, as well as including a control for whether that taxpayer received a bill or not. We then recover both the coefficient _β_ as well as calculate the control group mean _μ_ from each regression. The top half of Figure 3 shows (i) the distribution of those effect sizes across the 360 sub-wards, and (ii) the distribution of average control group compliance. The figures demonstrate a substantial amount of variation in effect sizes across strata. To give a sense of the implications for comparing small-scale experiments to city-wide ones: if the experiment had been conducted in a randomly-chosen strata, the chance that the resulting effect size would have been within one percentage point of the “true” effect estimate is only 58 percent. Only 65 percent of sub-wards had estimated effect sizes greater than zero.

The bottom half of Figure 3 compares the estimated distributions of control group compliance and treatment group compliance across strata. The bottom left graph shows that the distribution of treatment group compliance is shifted up and to the right of control group compliance. The scatterplot in the bottom right shows that the effect sizes are inversely proportional to control level compliance: the treatment seems to be more effective in areas that have a higher “baseline” rate of non-compliance.

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