responses is minimized. This issue is particularly important from a gender perspective in situations where women are main agricultural producers or where household members cultivate their individual plots. Finally, the fact that the crop monitor is a trusted local person will minimize _enumerator bias_ that might result from respondents suspecting that data will be used for taxation or other undesirable purposes.

To achieve this, the harvest diary, which complemented the standard two-round survey, was distributed to households at the time of the first round interview, to allow recording of all outputs from crop production at the time of harvest from that point on until the time of the next visit to the household, approximately five to six months later. The layout of the crop diary is straightforward: following general instructions,<sup>2</sup> it contains six monthly tables to record harvested quantities. Columns provide space to fill in the date of harvest, the crop name, local measurement units, quantity harvested, and any additional characteristics e.g. whether maize or beans was harvested fresh with cobs/pods or shelled and dry.<sup>3</sup> To prevent bias due to limited understanding or ability to fill the diary by households with low levels of education or literacy, implementation was supervised through fortnightly visits by a locally respected person, in most cases the schoolteacher, who, in return for a honorarium of about US $ 10 per month, acted as a monitor and who could also draw in help from other household members to help with filling of diaries. During these visits, entries for the previous period were reviewed to ensure their accuracy and make corrections as needed. The local monitor was also expected to code crops and measurement units so as to allow easy subsequent data entry. As diaries were collected by survey teams during their second visit, „completion‟ is defined as a household having continuously filled in the diary up to this point.<sup>4</sup> It must be noted that the amount of effort expended by UBOS on implementation of the diaries was very limited; i.e. there was neither a standardized training nor any written training material that would explain the exercise and the nature of the input expected from them to local monitors.

# **3. Assessing the suitability of using diaries**

A key concern raised in diaries surveys in the literature has been that their application may be biased in favor of the well-educated and that, after an initial period of enthusiasm, respondents‟ interest may well drop off, jeopardizing data quality. Our data allow us to empirically explore to what extent these concerns did arise in practice. We find that (i) the incidence of drop-outs is limited; (ii) non-response is more likely for the well-educated rather than the illiterate; and (iii) although the number of entries per crop declines slightly over the course of the survey, the number of crops remained virtually constant.

> 2 Respondents are reminded to fill in the booklet for any crop harvested as soon as possible after harvest.

> 3 In practice, conversion of local units proved to be a major issue as the size and kilogram-equivalent of local units varies by product and location. To deal with this and allow conversion of non-standard units such as heaps, bunches, buckets, baskets and tins, UBoS decided to subsequently administer a market survey that required enumerators to physically weigh all relevant units. Drawing on this information allowed us to include all the information recorded in non-standard units, thus make use of virtually all the observations in the 2005 UNHS.

> 4 The diary was expected to be collected during the survey teams‟ second visit which occurred on average some 5 months after the first visit.

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