data are representative at the wave level, so it is possible to compare the two waves in each country to assess the impact of seasonality.

In the absence of widespread irrigation systems, cereals are harvested only once a year from October to December; the agricultural lean season, which coincides with the rainy season, therefore runs from June to September while the pastoral lean season starts earlier and takes place between April and June. For Burkina Faso, Mali, Niger, and Senegal, the bulk of the interviews in the first wave took place between October 2018 and December 2018, although interviewing began in Burkina Faso and Senegal in September 2018 (see Annex 1). The second wave for these four countries was carried out between April 2019 and July 2019. Thus, for Burkina Faso, Mali, Niger, and Senegal, the first wave roughly corresponds with the harvest and immediate post-harvest (non-lean) season, especially as the 2018 rains arrived on time and resulted in above average biomass production (Action Contre La Faim, 2018). By contrast, the second wave captures the 2019 pastoral lean season and the first part of the agricultural lean season.<sup>9</sup> Since the timing of the EHCVM is similar in Burkina Faso, Mali, Niger, and Senegal, results from these countries can be pooled as well as presented separately. Annex 2 provides more detail on the timing of seasons in the Sahel.

The cross-wave comparisons for Chad will not be pooled with the other countries, given the timing of the EHCVM data collection there. In Chad, the first wave of the EHCVM data was collected between June and September 2018, which corresponds to the lean season of the 2017/2018 agricultural year, while the second wave was collected between January and April 2019. This differs too much from the data collection schedule in Burkina Faso, Mali, Niger, and Senegal for the data from all five countries to be combined when comparing the waves. However, Chad is retained for Section 3 to provide additional descriptive evidence on potential strategies for managing and coping with seasonality.

While useful, further temporal disaggregation to isolate how welfare differs for particular months of the lean season should be approached carefully. The timing of the second wave in the EHCVM data collection approximately coincides with the 2019 agricultural lean season for Burkina Faso, Mali, Niger, and Senegal, but the correspondence is not perfect. Indeed, the second wave starts and ends slightly too early in these four countries to capture the full extent of the 2019 agricultural lean season, and is better aligned with the pastoral lean season. Focusing on month-specific results may help to ascertain how welfare changes as the agricultural lean season evolves. However, the EHVCM is not designed to be representative at the month level, so these additional month-specific results should be interpreted with some caution.

Ramadan overlapped with the lean season in 2019, which could lead the analysis to underestimate the effects of seasonality. In 2019, Ramadan took place from 5<sup>th</sup> May to 3<sup>rd</sup> June, falling directly in the middle of the lean season wave of the EHCVM data collection. All of the countries in the sample are majority Muslim – with Mali, Niger, and Senegal being almost exclusively Muslim – so this may impact consumption patterns. All other things equal, consumption typically rises for Muslim households in Ramadan and reported food insecurity declines (see, for example, MVAM (2021)). Thus, it may be that the overall lean season losses estimated in this analysis represent an _underestimate_ of what might happen when Ramadan does not correspond with the lean season. Notwithstanding the caveats outlined above, looking at month-

> 9 The rains in 2019 arrived late in some western parts of the Sahel region, which may have led the 2019 lean season to arrive early as well, at least for pastoralists. However, the full effects of the late 2019 rains would be expected in 2020.

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