The name is absent

236

Table 8.4: Commercial farms survey: numbers of questionnaires mailed and returned
and estimated number of farms, by crop year, CSO, Zambia

a. Number of farmers to whom questionnaires were mailed.

b. The CSO published estimate of the number of commercial farms.
Source: Zambia CSO (commercial farms) series.

During the same period, response rates to mailed enquiries ranged from 22 to 34 percent.
Without a sampling of the nonrespondents, the representativeness of the voluntary respondents is
unknown. CSO officials recognized this problem as early as 1970 when they reported on a
nonresponse survey in the "1970 Agricultural and Pastoral Production Report." The exercise found
that the smaller farms on the commercial farms list had not received a questionnaire in the mail and
that the list was out-of-date because of the many changes in ownership.'

Over the last three years for which surveys were published, the number of questionnaires
mailed decreased significantly—down to 912 in 1986 and then to 180 in 1987. No numbers were
specified for 1988. Consequently, data collected during the last five years of the time series are likely
to be even less accurate than those collected during the first 10 years of the commercial farm survey.

While the exact procedures used by the CSO to arrive at the published estimates of commercial
agricultural production are not explained in the publications, the most common method, expanding

9

The reporting of this nonresponse study is the only comment found which indicated an attempt to access the quality
of the commercial farm data.

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