3.4.1. Agricultural Drought Resilience Index (ADRI)

Principal component analysis (PCA) was used to construct the agricultural drought resilience index (ADRI). Production of livestock in a normal year (WnPn), production of livestock with agricultural drought (WdPd), the number of months a household consumes food produced by the household in a normal year (WcnMn), and the number of months a household consumes food produced by the household in agricultural drought (WcdMd) were aggregated in PCA to develop the ADRI. The ADRI formula is expressed as (Equation (5)):

$$\rm{ADRI} = W\_{\rm{n}}P\_{\rm{n}} + W\_{\rm{d}}P\_{\rm{d}} + W\_{\rm{cn}}\mathbf{M}\_{\rm{n}} + W\_{\rm{cd}}\mathbf{M}\_{\rm{d}} \tag{5}$$

where W represents each component as a weighted linear combination of the variables and is determined from the component loadings from principal components with a zero mean and unit variance.

The four variables, production of livestock produced in a normal year (Pn), livestock produced in a year with agricultural drought (Pd), the number of months a household consumes food produced by the household in a normal year (Mn), and the number of months a household consumes food produced by the household in drought (Md), were analyzed using Bartlett's test of sphericity and Kaiser–Meyer–Olkin (KMO) using SPSS software.
