269
IV.5 Cluster size and number of clusters
The cluster size in the ALCS 2013-24 was maintained at ten households. There is a pragmatic upper limit to the cluster size, given the time and costs involved in reaching remote villages and the lack of
accommodation for fieldworkers – especially female staff – in such areas. In addition, the specific
conditions in Afghanistan prescribe that in insecure areas the field staff should not be exposed to risks of a stay of more than two days in the interview area. Ten household interviews plus one Shura
interview is the maximum that can be achieved in two days time. The cluster size of ten, in combination with 35 strata and a total sample size of 21 thousand, implies on
average 60 clusters per province and five clusters 50 households per province per month.
IV.6 Sampling stages and selection process
Within each of the 34 provincial strata EAs were selected as PSUs in the first sampling stage, based on PPS. In the second stage a cluster of ten households was selected from the updated household listing,
based on a fixed-interval and random-start procedure. In rural EAs that contained more than one village, a third sampling stage was introduced to select one of the villages, as it was not feasible to cover different
villages during the household update prior to the fieldwork. In order to accommodate for possible non-response different procedures were devised. Non-response
within a cluster was addressed by drawing an additional five households from the household listing in the EA, which could replace households not present or refusing or not able to accommodate an interview.
Replacement of selected EAs that were not accessible due to physical access mainly in winter time or insecurity was done by using sampled EAs from later months in the survey period. This principle was
based on the assumption that physical access in another time of the year would be feasible and that security is a fluid condition, which may improve over time. However, in a later stage of the fieldwork
an alternative strategy was devised to replace clusters in insecure areas. A reserve sample of PSUs was drawn from the sampling frame, from which districts that were defined as insecure by the supervisors
and PSOs were excluded, as well as EAs that were originally sampled. EAs that were originally selected in these districts and not yet covered were replaced by EAs from this reserve list. Isolated emerging
security issues in other districts could also urge the use of replacement from this reserve list. The districts excluded from the reserve sample list are listed in
Table IV.1
. For the Kuchi stratum a first-stage PPS selection of Kuchi communities was carried out on the basis of
the NMAK list. The second stage consisted of systematic sampling of clusters of ten households, based on a field compilation of tents and permanent dwellings occupied by Kuchis. This resulted in large
communities having more than one cluster, up to a community with nine clusters.
270
Table IV.1 Districts excluded from sample frame for reserve sample
IV.7 Sample design implementation
Kategori