production, etc.) and livestock (cattle, sheep, fish farming, etc.). For each of the settlements, summary statistics are presented in Table 1. On average, settlements derived 71% of their income from agricultural activities, with a minimum of 0% and a maximum of 100%. We also tried to include additional measures of economic activity, such as the average income level in the settlement and the share of employment in the service sectors (both only available for 2020). None of these yielded significant results and were hence not included in the regressions.

Yet limitations in the data available reduce our ability to fully disentangle the interaction between displacement flows, economic growth, and NTL evolution. One should then refrain from making strong inferences in terms of causality, as this paper mainly captures complex correlations.

# 4. Regression Analysis

In this analysis, we regress the NTL growth on the total level of displacement in the settlement, represented by the cumulative net inflow of displaced persons over the 2018-2020 period. The linear regression will return information on the general evolution of NTL, i.e., whether and how cumulative net inflow of displaced persons correlates with higher NTL growth.

## 4.1. Benchmark NTL growth

This section explores the NTL growth rate observed in Badghis, i.e., the NTL evolution over time, before accounting for potential deviations from displacement patterns. NTL patterns indicate improvements in overall electrification or an increase in other ambient light sources, like fires in previously electrified areas, and increases or appearance of electrification in areas with little or no historic light emittance. These findings can be shown by Li et al. (2020), which used global NTL time-series data (1992–2018) to show that the NTL time series experienced a trend of both increasing NTL and continuous spatial expansion for high luminance pixels, both in urban centers and fringe locations. This indicates that the NTL growth rate for a given area will primarily exhibit an increase in overall average NTL for an already electrified area or will indicate the presence of new electrification in areas with improved infrastructure or newly inhabited areas. While there is often growth and expansion of NTL over time, baseline NTL levels remain relatively constant due to existing infrastructure and outdoor lighting, with fluctuations over time reflecting shifts in population or economic activity.

To control for population size and level of economic activity, the analysis includes a benchmark population estimate (2017) and a measure of the share of agricultural income at the settlement level. Keeping in mind that the cumulative net inflow is based on the 2018 to 2020 flows of persons, the population levels of 2017 allow to proxy for initial urbanization levels and find the relevant benchmark to each settlement.

The first column of Table 2 displays the linear regression of NTL levels on its past values at the settlement level, controlling for district-fixed effects. As seen previously, there are 294 settlements spread across seven districts. Let’s define N the average NTL in the 1km buffer around the settlement _i_ in district _j,_ at date _t (_ each month from Jan 2018 to Jan 2020) _._ The following regressions looks at how the NTL levels naturally grow through time in ii,jj,tt settlements within Badghis province, accounting for the initial population in 2017, the share of community income LL derived from agricultural and livestock activities in late 2020, time seasonality ( μ the time fixed effect) and the fixed effect for district _j_ : tt jj δδ N = β0 + β1N 2P 3A A + μ (1) Table 2 (column 1) shows that the benchmark growth of NTL levels is positive on average, i.e., a 1-unit increase in past ii,jj,tt ii,jj,tt−1 ii ii jj tt ii,jj,tt LL LL + ββ PP2017 + ββ AA2020 + δδ + uu NTL value in an IOM settlement always raises the current NTL value.

Quadratic robustness. Appendix C expands the analysis with a quadratic model. The regression analysis of the growth rate of NTL in Badghis settlement is positive and concave, as settlements with higher NTL in period t-1 will experience larger NTL in period t. The quadratic regression suggests that the NTL growth follows a concave shape; that is, settlements with the largest expansion are those with the lowest level of displacement inflow to start with. On 8