Imputation method for lifetime exposure assessment in air pollution epidemiologic studies

Table 2 Distribution of women by limits on incompleteness index (PDI ^a ) in cumulative dose for one imputed data set ^b (Women who arrived before 1996)

Limits on PDI^a	Number of control women	Number of case women	Total
Zero (complete coverage)	267	280	547
>0 and < 20%	336	281	617
20% to < 40%	164	149	313
40% to < 60%	150	137	287
60% to < 80%	136	151	287
80% to < = 100%	465	470	935
Total	1518	1468	2986
Probability level for Chi-Square			0.13

^aPDI = Percent of dose imputed.
^bThe Chi-square probability level can vary between low (0.04) and high (0.31) values for different imputed data sets.

ISSN: 1476-069X