Unexpected Changes in Sample Demographics

Your study sample contains adequate representation of minorities.  During the course of data collection, however, an unexpectedly large number of minority subjects must be dropped for various reasons, leaving insufficient representation of one minority group.  It is too late to recruit additional study subjects.  Do you:

1. Request an exemption from the requirement for minority representation.
2. Discard the study data and start again.
3. Proceed as though all minorities were represented adequately, ignoring the attrition in study subjects.
4. Perform a second study using only subjects from the under-represented minority.

J1G says:  None of the above.  Subject recruitment is part of the study, not a preliminary step.  Report the difficulty with minority subjects' completion of the protocol.  It's a finding.

R3H says:  None of the proposed alternatives is acceptable.  Subject selection was part of the study design which cannot be changed after the fact.  The study result is the study result and the fact that particular groups had difficulty with the study is part of the result.  It is not ethical to delete or ignore data under these circumstances.  There are statistical techniques, such as intention to treat analysis, that may be helpful and consultation with a statistician may be considered, even after the fact.