With an increase in the frequency of unforeseen extreme weather events that threaten seasonal crop production and thereby rural livelihoods (McCarthy et al., 2017), cassava cultivation is garnering more attention, as also evident in the National Agricultural Policy (MoAIWD, 2016). The promotion of cassava production and value addition in Malawi requires a change in the approach to public spending on agriculture, of which an average of 50 percent was geared towards maize production during the period of 2006-2013 (FAO, 2014). To inform such process, one needs reliable time series data on cassava cultivated area, production and yields. Currently, there are at least two sources of annual, national-level cassava statistics in Malawi.P6F<sup>7</sup> Agricultural Production Estimates Survey (APES), which is conducted annually by the Ministry of Agriculture, Irrigation and Water Development (MoAIWD), is the first source. APES approach to cassava yield estimation is based on crop cutting, although the operational documentation on the APES cassava crop cuts, specifically their supervision, timing and processing, is not available. The latest publicly available APES report for the 2015/16 season reports a national cassava yield of 17,564 kilograms per hectare (kg/ha). The same report puts the figure for the 2014/15 season at 18,042 kg/ha.P7F<sup>8</sup> FAOSTAT is the second source of cassava statistics in Malawi. Figure 1 shows the FAOSTAT national yield and harvested area estimates from 2005 to 2014 (i.e. the latest year for which the estimates are available). The exact details on the computation of the FAOSTAT-based statistics are not available, and they are presumably at least in part a function of the information provided by the MoAIWD in response to the annual FAOSTAT questionnaire. If true, the increase in the national cassava yield from 14,300 kg/ha in 2005 to 22,504 kg/ha in 2014, as well as the parallel surge in the harvested area from 153,687 hectares to 222,750 hectares during the same period would be remarkable.P8F<sup>9</sup> However, given the lack of immediately-accessible documentation on the generation of the APES and FAOSTAT estimates (and disregarding for now the discrepancies between them), it is not clear whether these yields capture potential, attainable, economic or actual yields, as defined later in section 3.4.

# **3. Data**

To investigate the relative accuracy and cost-effectiveness of a range of survey methods vis-à-vis their gold standard counterparts in the areas of cassava production and productivity measurement, as well as cassava variety identification, the Malawi National Statistical Office (NSO), in collaboration with the World Bank Living Standards Measurement Study (LSMS) and the CGIAR Standing Panel on Impact Assessment (SPIA), implemented a randomized household survey

> 7 A third source is the Integrated Household Survey (IHS), which is conducted by the National Statistical Office (NSO). Previous rounds of the IHS that could be used for computing national estimates of cassava production and yield are 2004/05 (IHS2), 2010/11 (IHS3), and 2016/17 (IHS4).

> 8 The time series information on cassava production and yield was not available on the MoAIWD website at the time this paper first appeared online.

> 9 The available statistics in fact date back to 1964, supportive of the upward trend observed for the 2005-2014 period.

6