The irst phase of the two-stage training consisted of one week class-room training and two days of ield practice under supervision of CSO staff, and was concluded with an exam. The exam scores and a review of completed questionnaires
were used to select the supervisor and two interviewer couples for each province. These 34 supervisors and 136 interviewers continued class-room training for another 15 days. The trainees not selected for the ieldwork were kept as
reserves to accommodate drop out during the survey period. In addition to the initial central training, at the end of the irst three quarters of data collection regional workshops were
conducted for supervisors, Provincial Statistical Oficers PSOs and Regional Statistical Oficers RSOs. The aim of these workshops was to feed back the lessons learned from the ield, discuss relevant issues, provide additional training,
transfer new ield supplies and strengthen working relations and coordination between PSOs, RSOs, ield supervisors and Headquarters staff. In March 2012 another round of regional training was conducted for all ield staff, including PSOs
and RSOs, with a special focus on the food consumption modules. After completion of the survey, a inal series of regional debrieings was organised for ield staff in order to obtain their
views on improvements in ield procedures and questionnaire design and contents. This feedback has been incorporated in the development of the next survey round in 2013.
2.6 Sampling design and implementation
The sampling design of the NRVA 2011-12 was developed to produce results that are representative at national and provincial level, as well as for Shamsi calendar seasons.
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In total 35 strata were identiied, 34 for the provinces of Afghanistan and one for the nomadic Kuchi population. Stratiication by season was achieved by equally distributing data
collection over 12 months within the provinces. For the Kuchi population, the design only provided sampling in winter and summer when communities tend to temporarily settle. Given the total sample size of 21,000 and uniform sample size per
stratum, each province and the Kuchi stratum was assigned with 600 households to be interviewed.
The sampling frame used for the resident population in the NRVA 2011-12 was the pre-census household listing conducted by CSO in 2003-05. Households were selected on the basis of a two-stage cluster design within each stratum. In the
irst stage Enumeration Areas EAs were selected as Primary Sampling Units PSUs with probability proportional to EA size PPS. Subsequently, in the second stage ten households were selected as the Ultimate Sampling Unit USU. The
design thus provided for 60 clusters per province, implying data collection of ive clusters 50 households per province per month and in total 170 clusters 1,700 households per month and 2,040 clusters 20,400 households in the full year
of data collection.
The Kuchi sample was designed on basis of the 2003-04 National Multi-sectoral Assessment of Kuchi NMAK-2004. For this stratum a community selection was implemented with PPS and a second stage selection with again a constant
cluster size of ten households. The 60 clusters 600 households for this stratum were equally divided between the summer and winter periods within the survey period.
The reality of survey taking in Afghanistan imposed a number of deviations from the sampling design. In the irst six ieldwork months areas that were inaccessible due to insecurity were replaced by sampled areas that were scheduled
for a later month, in the hope that over time security conditions would improve and the original cluster interviews could still be conducted. In view of sustained levels of insecurity, from the sixth month of data collection onward clusters in
inaccessible areas were replaced by clusters drawn from a reserve sampling frame that excluded insecure districts. In
addition, delays in ieldwork caused an uneven seasonal coverage. Sample weights were calculated for up-scaling the surveyed households and population to the total number of households
and population in Afghanistan. The calculation was based on the oficial CSO population estimate by province for January 2012 and average provincial household size derived from the survey. In view of the unequal distribution of the sample
across seasons, a post-stratiication adjustment was imposed to give equal weight to the seasons. Annex IV gives an account of the background and technical details of the sampling design and implementation.
5 The Shamsi years 1390 and 1391, in which the NRVA 2011-12 was conducted, run from, respectively, 21 March 2011 to 19 March 2012 and from 20 March 2012 to 14 March 2013. Season dates are given in Annex IX.
SURVEY METHODOLOGY AND OPERATIONS
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