Attrition was remarkably low in the Tongan sample. Of the 448 households in the baseline, we were able to re-interview 442 households in the second round survey, 444 in the third round, and 440 in the fourth round. In contrast, attrition was higher in Vanuatu. Of the 456 households in the baseline survey, 382, 388, and 348 households were re-interviewed in rounds 2, 3 and 4 respectively, whilst 33 households were only interviewed in round 1. The higher attrition rates arose from i) internal mobility, with a few households moving to other islands within Vanuatu that were not part of the three where we were surveying; ii) cases where the RSE worker died and the rest of the household moved; iii) respondent fatigue, with some of the non-RSE households complaining that their lives had not changed at all, so why were we asking the same questions over again; and iv) 8 cases where husbands or wives divorced while the other was away in New Zealand, and the worker refused to answer. In an appendix we show our main results are robust to this attrition.

# **3.2 Estimation methodology**

We consider two measures of a household’s participation in the RSE. The first is a binary indicator _RSEi,t_ of whether household _i_ has at least one member who has worked in the RSE by time _t_ , where _t=1,2,3_ and _4_ corresponds to our four survey waves. This variable takes value zero in the baseline for all households, and then switches on once a household participates in the RSE. Estimating the impact of _RSEi,t_ then involves estimating the average impact of ever participating in the RSE over the first two years of the program.

However households varied substantially in the degree of their exposure to the RSE. This variation in the intensity of RSE participation arose from i) differences in the duration of a contract, with contract durations varying between three and seven months, and a small number of workers returning after only one or two months before their contract had ended; ii) differences in whether workers returned for a second or even third contract during our survey period; and iii) a handful of households having more than one worker participate in the RSE.<sup>10</sup> We therefore define a second measure of household RSE participation, _RSEDurationi,t_ , as the cumulative number of months workers from household _i_ have spent in New Zealand by time period _t_ . Among the RSE households in our Tongan sample, the mean (median) cumulative duration in New Zealand by the time of our fourth round survey was 7.8 months (6 months), with a 10<sup>th</sup> percentile of 3 months and 90<sup>th</sup> percentile of 14 months. For RSE households in Vanuatu, the mean (median) at the time of the fourth round survey was 8.4 months (7 months), with a 10<sup>th</sup> percentile of 4 months and 90<sup>th</sup> percentile of 14 months. 58 percent of Tongan RSE households

> 10 For the RSE as a whole, 23 percent of workers spent 3 months or less in New Zealand, 18 percent spent 4 months, 20 percent spent 5 months, 27 percent spent 6 months and 11 percent spent 7 months (as of August 23, 2009, see Table 5 of New Zealand Department of Labour, 2010). 51 percent of workers from kick-start states from the first season returned in the second season.

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