the Subsample Imputation approach needs a large sample of nonconsumption data. The government of Bangladesh recently carried out a simpler version of the HIES to collect nonconsumption data, the Welfare Monitoring Survey (WMS). It simplified the HIES questionnaire significantly and does not include consumption and income data. According to the BBS, WMS implementation costs are only around one-tenth of the HIES.

How do the implementation costs of the HIES compare with those of the WMS and a collection of a subsample of consumption data? Although this cost estimation is admittedly rough, it was carried out in close collaboration with BBS survey experts to incorporate several aspects of the survey data collection process. In terms of the WMS sample size, we tentatively assumed that 12,240 households formed 612 PSUs, following the sampling frame of the latest round of the HIES (2010). Instead of estimating survey implementation costs in local currency, we estimated three key aspects of survey implementation, namely staff weeks, number of moves and days of lodging, which are all closely related to survey implementation costs. For example, the number of moves should be closely related to transportation costs, the days of lodging should be proportional to the total lodging cost, and the staff weeks should be proportional to the total staffing costs.

This cost comparison also included an experiment: switching the mode of consumption data collection from a diary-based approach to a recall-based approach. Consumption data in the HIESs are collected by a diary-based approach, or more precisely, seven consecutive visits by enumerators to a household to collect the last two day’s consumption data. In this sense, the approach undertaken in the HIES could also be considered a recall-based approach, but since consumption data are collected in an almost continuous manner for two weeks, we call it a diary-based approach.

Obviously, the diary approach is very costly since a group of enumerators needs to stay in a village for 14 days to collect consumption data. If consumption data were collected in one visit with two weeks of recall, then the cost of implementation would be much cheaper. But this can cause comparability problems between the consumption data and data from previous rounds. Beegle et al. (2011) reviewed previous studies on this method of consumption measurement and noted that “well-implemented diary surveys might be expected to yield higher (and presumably closer to actual) levels of consumption, experimental evidence for this from developing countries is fragmentary.” The following analysis finds cost savings from switching from the diary approach to the two-week recall approach, and shows the impact of switching on comparability, based on analysis from pilot survey data.

# **Costs of WMS as Baseline and Assumptions for Estimation**

WMS costs were used as a baseline. In the WMS, consumption data are not collected, and without he consumption module the survey is shorter than the HIES. Therefore, after consultation with BBS survey experts, we assumed that one enumerator could handle the survey in two PSUs for one week. So, the total staff weeks for 612 PSUs was equal to 306 (612 PSUs × 0.5 week). In addition, the number of movements is assumed to be proportional to PSUs covered by the number of enumerators, and the days of lodging are assumed to be (the number of PSUs) × (the number of weeks) × 7. So, the number of movements is 612, and the days of lodging are 2,142 (= 612 PSUs × 0.5 week × 7) days.<sup>4</sup>

# **HIES Costs Compared to WMS Costs**

Compared to the WMS, the HIES questionnaire is much more detailed and comprehensive. For example, even if the questionnaires of both the WMS and HIES include an education section, the HIES ask many more questions in the section than the WMS. Also, the HIES questionnaire includes questions regarding economic activities and agricultural and nonagricultural enterprises, which are not included in the WMS. Collection of consumption data for the HIES requires seven visits to each household in two weeks. After consultation with BBS survey experts, we assumed as reasonable the following regarding staff weeks, number of moves, and days of lodging: 21