all interviews were conducted by experienced team of interviewers trained by Ipsos. Because of technical problems, data related to the labor force participation module of the questionnaire were not collected properly and could not be used in the analysis. Given the relevance of employment outcomes for the study, Ipsos conducted a new wave of phone call interviews in July 2014 for just a few demographic variables (to confirm the identity of respondents) and for the employment module seven months after the first endline survey and about 14 months after the participants had completed the program (Table 1).

Thus, the variables related to demographics, education, training, skills, health, and saving behavior were collected in the first in‐person endline survey, while the variables related to employment and past employment were collected in the phone call interviews (second endline). The final sample for labor market outcomes included 1,618 youths: 709 in the control group, 657 in the T2 (full program) group, and 252 in the T1 (life skills only) group. The final sample for intermediate outcomes such as skills and socioeconomic outcomes includes 1,635 individuals (Table 2). The composition of the final samples by group assignment, location, and gender is shown in table 3.

To minimize the risk of attrition, Ipsos collected detailed contact information in the baseline survey, including each youth’s physical address, email address, landline, and cell phone numbers as well as the landline and cell phone numbers of their parents and closest friends. All those interviewed in the baseline survey had working cell phone numbers. Follow‐up telephone calls were made to keep track of the respondents by KEPSA and through the Computer Assisted Telephone Interviews (CATI) system within Ipsos to validate and update this information during the months between baseline and endline surveys. Ipsos also tried using the additional contact information for relatives and friends that had been collected in the baseline survey, but this information did not prove to be very reliable. However, there were high attrition rates in both endline surveys (22 percent and 23 percent respectively), mainly due to cell phone numbers being switched off, the high internal mobility of youths within urban areas, and their lack of interest in participating in the endline survey.

Baseline statistics reveal high youth mobility, with 56 percent of youths having lived outside Nairobi and Mombasa and almost half of the sample having moved residence more than twice in the previous two years. Internal migration was particularly high in the Nairobi sub‐sample, where 67 percent of the youths reported having lived in another region before. The highest migration was from Nyanza region. Most of the youths who moved to Nairobi came from the Nyanza and Central regions, while most of those who moved to Mombasa came from the Nyanza, Western, and Eastern regions. Almost 40 percent of those migrating from other regions in Kenya reported having come to either Nairobi or Mombasa when they were between 18 and 21 years old. Very few migrated from other countries.

The attrition rates recorded in both endline surveys (22 percent and 23 percent) compare favorably to similar studies on youths in urban areas in other developing countries, for example, 18.5 in Colombia (Attanasio et al, 2011), 38 percent in the Dominican Republic (Card et al, 2011), and 46 percent in Malawi (Cho et al, 2013). More importantly, the treatment and control individuals had different attrition rates in both of the endline surveys. Table 4a shows that attrition rates were overall higher in the control group than in the treatment groups in both cities and were far higher among females than males. Attrition rates for females assigned to the control group were about 30 percent in both Nairobi and Mombasa, but differential attrition (the attrition rate of the control 11