In this design, no baseline data was collected for the project group or a comparative (non-project) group and relies completely on end-of-project comparisons between the two groups. This design can be used when do baseline data study was conducted due to time, funding, staffing or situational (e.g., conflict) constraints, or if a baseline cannot be reconstructed (Michael Bamberger has written extensively on reconstructing baselines). It is more effective when used in isolated communities or settings that have little or minimal outside influences (which is getting hard to find these days).
The basic flaws of this design are that it does not account for possible influencial historical events, substantial pre-existing differences, or possible differential trajectories over time between the two groups.
To improve on this design, other methods need to be used such as key informant interviews, focus group discussions, in-depth interviews, and personal history recall.