RESEARCH METHODS-QUALITATIVE STUDY DESIGNS-BASING ON NATURE OF THE INVESTIGATION-THE BEFORE-AND-AFTER EXPERIMENTAL DESIGN

The before-and-after design overcomes the problem of retrospectively constructing the ‘before’ observation by establishing it before the intervention is introduced to the study population. Then, when the programme has been completely implemented or is assumed to have had its effect on the population, the ‘after’ observation is carried out to ascertain the impact attributable to the.  The before-and-after design takes care of only one problem of the after-only design – that is, the comparability of the before-and-after observations. It still does not enable one to conclude that any change – in whole or in part – can be attributed to the programme intervention. To overcome this, a ‘control’ group is used. Before-and-after designs may also suffer from the problems identified earlier in this chapter in the discussion of before-and-after study designs. The impact of the intervention in before-and-after design is calculated as follows:
[change in dependent variable] =[status of the dependent variable at the ‘after’ observation] –[status of the dependent variable at the ‘before’ observation].