bd CPS: bug - median hourly real wage giving odd results about econ_data

[bdecon]

Verify that the interpolation step is handled correctly. Per the EPI methodology:

For these reasons, we enforce some smoothness in the wage data to ensure that exactly 10 percent of our sample falls at or under the 10th percentile wage (and 20 percent falls under the 20th percentile and so on). The smoothing technique involves creating a categorical hourly wage distribution, in which the categories are 25-cent intervals (also referred to as 25-cent bins). We then find the bins on either side of each decile and perform a weighted, linear interpolation to locate the wage cutoffs for each of the particular deciles. The weights for the interpolation are derived from differences in the cumulative percentages on either side of the decile. For example, suppose that the 48th percentile of the wage distribution of workers by wage level is in the $9.51–$9.75 wage bin, and the 51st percentile is in the next higher bin, $9.76–$10.00. The weight for the interpolation (in this case, the median, or 50th percentile) is (50–48)/ (51–48), or two-thirds. The interpolated median equals this weight, times the width of the bin ($.25), plus the upper bound of the previous bin ($9.75); $9.92 in this example.

[bdecon]

By shrinking the bin size, the results look much better. Still, I have not verified that the methodology matches that used by Census/BLS/EPI. Closing the issue.

[bdecon]

There are still large jumps in the data. They are disguised by the moving average but much larger than I would expect. Reopening the issue to investigate.

[bdecon]

I've been able to match BLS data fairly precisely. I'm not sure what the problem was in the cases, but if it happens again I will re-open this and add an actual example.