underestimate (overestimate) measured land productivity. Second, of all the productivity measures, labor productivity per worker measured at the plot-level is most likely to be overestimated by the recall method. This is because listing bias in persons reduces the denominator and (unlike with labor productivity per hour) is not counteracted by positive recall bias in hours per person-plot conditional on being listed. Third, even if labor productivity per worker is overestimated at the plot-level, it could still be underestimated at the household-level. This is because listing bias in plots reduces measured output (in the enumerator), but may not necessarily reduce the number of workers (the denominator), unless some workers worked exclusively on non-listed plots.

To assess the impact on different measures of productivity empirically, we use data on crop production collected at endline. As discussed in section 2, the endline survey fielded a standard agricultural production module to all households, which asked to report the quantity and value of crop harvested during the preceding agricultural season (for each plot and crop). Hence households in the weekly visit and recall groups reported on their plot-level harvest in the same manner. Using these harvest data, we measure plotlevel yields and labor productivity for maize as the maize harvest in kg or in cedi per acre, per labor hour, and per worker.<sup>13</sup> All measures are winsorized at 1 percent and the analysis is conducted at the plot-level. **Table 13** presents regression estimates of recall bias.

**Table 13: Yields and labor productivity in maize production, recall and weekly visit groups**

||Landpro|ductivity|Laborproducti|vity (per-hour)|Laborproductiv|ity (per-worker)|
|---|---|---|---|---|---|---|
||Cedi/acre|Kg/acre|Cedi/hour|Kg/hour|Cedi/worker|Kg/worker|
||(1)|(2)|(3)|(4)|(5)|(6)|
|Recall|21.543|28.358|2.633|4.656**|264.322***|415.993***|
||(31.903)|(48.880)|(1.691)|(2.359)|(88.471)|(118.681)|
|N|493|491|487|485|487|485|
|R2|0.019|0.014|0.040|0.045|0.099|0.112|
|Control Mean|457.62|728.15|9.20|13.79|555.65|837.26|

Note: All dependent variables are winsorized (1%). Regressions control for household size, number of plots, and the average distance between the household’s residence and the plots (all at baseline). Standard errors in parentheses. *** denotes significance at the 1% level; ** at the 5% level. Control Mean shows the mean value of the dependent variable for Weekly Visit households.

We find no evidence of significant recall bias in maize yields, which broadly confirms our expectations that measures of land productivity should be fairly robust to the types of measurement bias that are the focus of this study. Maize yields (columns 1 and 2) are somewhat higher among recall households, but not statistically significantly so, suggesting that listing bias in plots does not affect yield measures (or, in other words, any productivity differences between omitted and listed plots are too small to affect average maize yields). However, for three of the four measures of labor productivity in agriculture (columns 4 to 6), we find it is significantly overestimated among recall households. In line with our expectations, the recall effect is more significant (both economically and statistically) for labor productivity per-worker than for labor productivity per hour – this is because listing bias has a proportionately larger effect on the number of

> 13 Hired labor is not included to maintain simplicity in the comparisons.

21