Point estimates of policy effects using difference-in-differences can be generated by simply calculating the difference in means for a given outcome between treatment and comparison groups
, before and after the intervention was initiated.
The comparison group
consisted of a pool of seven countries (Cameroon, Congo, Ethiopia, Gabon, Mozambique, Nigeria and Tanzania) that did not change their delivery fee policies.
There was a tendency toward lower Hia SBA GMTs in both Aboriginal and non-Aboriginal CRF-patient groups compared to their corresponding healthy comparison groups
, but the differences were not statistically significant (Table 2).
No substantive differences were found from baseline to first-year follow-up between the intervention and comparison groups
in analyses of the major study survey measures.
Among women, 20 who took B vitamins and 9 in the comparison groups
developed cancer, a difference of borderline significance.
We re-matched the RTA and comparison groups
on the basis of DOCS entry date, but found that four of the comparison men did not meet the one-year criterion, and eliminated them and their matched counterparts in the RTA group.
The IF and comparison groups
were well matched in terms of their demographic characteristics and criminal histories.
The findings showed that both the exercise and comparison groups
had a smaller COM-COP inclination angle (M angle) during the dual task condition.
Following descriptive analyses, chi-square and t tests were conducted to determine differences between intervention and comparison groups
for youth and parent sample characteristics.
We tested for differences in demographic, clinical, and utilization characteristics between the intervention and comparison groups
in the year prior to the start of each pilot to determine whether differences emerged between the intervention and comparison groups
due to the lag between the randomization and the start dates.
ORF mean scores were similar in the treatment and comparison groups
in winter (treatment: M = 19.
It followed 98 children who had an autism spectrum disorder and two comparison groups
, 52 children with special educational needs but no evidence of autism spectrum disorder, and 90 children who were normal.