# **2. Data**

# **Sampling design**

The overall evaluation design includes a series of household and child surveys, beginning with a baseline survey in 2001. Three surveys of the same sample of about 5,000 households from two of the program regions (Region 6 and 7) and a non-program region (Region 8) have been completed.<sup>7</sup> In each round, data were collected also from local officials and ECD service providers. The sampling strategy involved stratifying the barangays in each province into (1) pilot barangays that were supposed to have participated in a pilot phase launched in 1998,<sup>8</sup> (2) program or target barangays in Phase 1 of the project, and (3) non-program barangays or non-targeted barangays in the (pilot and Phase 1) program and non-program municipalities in the region.<sup>9</sup> In each program region, five pilot and five non-program barangays were randomly chosen, while the remaining barangays were drawn at random from the program barangays. In Region 8, sample barangays were randomly chosen from all barangays, with the number of barangays chosen proportionate to the total number of barangays in each province. In each sample barangay, an average of 24 eligible households (i.e., households with 0-6 year-old children or households with pregnant women) in Regions 6 and 7 and 14 households in Region 8 were selected. The overall response rate was high at 96 percent. During the baseline survey, 7,922 children aged 0-4 were selected to be followed up in the succeeding rounds; children aged 5-6 years old were not included for the evaluation sample because they were too old to be exposed much to the program. All estimates are weighted to account for the sampling scheme.

Of the original cohort of 7,922 children age 0-4, 86 percent (or 6,774 children) were successfully followed up _in the same barangays_ in the first follow-up survey in 2002 (Round 2) and the second follow-up survey in 2003 (Round 3) (see Table B.1). For cost reasons, we only tracked and attempted to interview children in households whose members migrated to another barangay within the same province (399 children or 5 percent of the sample). Out-migration to a non-sample barangay outside the sample municipality or province was the main reason for attrition (552 children). Another 197 children were lost due to deaths, refusals or incomplete interviews. The overall attrition rate by Round 3 was 9 percent (or 749/7922). This attrition rate is comparable to other longitudinal surveys in developing countries (e.g., Alderman, _et al._ 2001a) though higher ________________ 7 The baseline survey was conducted in April-August 2001; the first follow-up survey was fielded in September-November 2002, and the second follow-up in September –November 2003.

8 Although the pilot barangays were supposed to have received initial ECD project inputs prior to the data collection phase of this study, these project inputs were delayed. As discussed in the section on Data and Methodology, we exclude from our estimation sample all barangays that received project inputs prior to the baseline Round 1 data collection.

9 This classification was based on a list of program barangays provided by the Project Management Office (PMO) and verified with the DSWD field offices in the respective areas.

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