Table 1.

Changes implemented during phase 2 of longitudinal study

Study modification	Month/year implemented	Subjects affected	Impact on study
1. Telephone follow-up	May 2005	45	a
2. New interviewing modules	May 2005	79	b
3. Increasing sample size	June 2005	51	c
4. Brief follow-up	June 2005	12	d
5. Psychological testing	August 2005	34	d
6. Super follow-up	September 2005	29	e
7. Continuing New Orleans site	November 2005	8	d

^aPermitted communication and completion of interviews among subjects traveling outside of Los Angeles.

^bIncreased subjects’ interest in follow-up interview and facilitated completion of interviews.

^cEnabled larger pool of subjects to be recruited and retained during longitudinal study.

^dIncreased retention rate.

^eEnabled subjects recruited late in the study to complete all new interviewing modules.