Table 6

Absolute frequencies, outcome prevalences, exposure prevalences, crude and pooled prevalence ratio (PR) estimates, and relative confounding for the analysis of the modified data using mother in a paid job as the outcome, father living with the family as the risk factor and social class as confounder (situation 3 modified).

First stratum: High social class


Mother employed
No
All





N
Prev.
N
N
Prev. exp. = 15.0%




Father Present
73
90.1%
8
81
PR = 1.80
No
230
50.0%
230
460
M-H weight = 34.44
All
303
56.0%
238
541


Second stratum: Low social class


Mother employed
No
All





N
Prev.
N
N
Prev. exp.= 80.0%




Father Present
295
56.0%
232
527
PR = 1.39
No
53
40.2%
79
132
M-H weight = 42.38
All
348
52.8%
311
659


Combined strata: High and low social class


Mother employed

No
All
Prev. exp.= 50.7%




N
Prev.
N
N
PR (crude) = 1.27




Father Present
368
60.5%
240
608
PR (M-H) = 1.58
No
283
47.8%
309
592
Confounding = 24.6%
All
651
54.3%
549
1200
P-value(het) *= 0.01

* P-value for testing heterogeneity of the prevalence ratios across strata.

Barros and Hirakata BMC Medical Research Methodology 2003 3:21   doi:10.1186/1471-2288-3-21