Nigeria - National Survey of Agricultural Export Commodities 2006, Third round

The first frame was the list of 774 LGAs nationwide. The second frame was
the list of EAs demarcated by the National Population Commission during
the 1991 population census.
2.4 REPORTING DOMAIN
The reporting domain was the state. Summation over the states gave an
indication for the national estimates.
2.5 SAMPLE DESIGN
192 LGAs were selected nationwide.
A 2-stage sample design was employed.
In the first stage,I0 EAs were systematically selected from each
sampled LGA. Of the expected 1,920 EAs, only 1,855 were found to have
export crops and were eventually studied.
In the second stage, 10 export crop farming housing units were systematically
selected from each sampled EA (provided there were more than 10 farming
housing units in the EA). Where there were 10 or less farming housing
units, no selection was required and all available housing units were
studied.
Out of the 18,550 export crop farming housing units expected to be covered, 16,310 were canvassed.


No deviation


On National basis, 100 percent response rate was acheived at LGA level and 96.61 percent at EA level
while 87.92 percent was acheived at export crop farming housing units level.


The variable (Rf) Rasing factor is computed and attached to the data file.

The formula adopted in calculating the design weights for the survey data (sample results) were as follows:
(i) The probability of selecting an EA within a state was obtained by dividing the total number of EAs sampled in a state by total number of EAs in that particular state. Let this be represented by fj. That is,
fj = Total Number of EAs sampled in a state
Total Number of EAs in that particular State

(ii) Likewise, the probability of selecting an housing unit (HU) within an EA was obtained by dividing the total number of housing units selected in an EA by the total number of housing units (HUs) listed in that particular EA. Let this be represented by fk. That is,
fk = Total Number of HUs selected in an EA
Total Number of HUs listed in that particular EA
Mathematically,
Design weight = Total number of EAs in a state
Total number of EAs sampled in that particular state
X
Total Number of HUs listed in an EA
Total Number of HUs selected in that particular EA