1. FRAMES FOR AGRICULTURAL CENSUS AND SURVEYS

2. INTRODUCTION  The Samoan households survey framework incorporates the following sampling schemes ٭ Stratified sampling. ٭ Stratified sampling. ٭ Two Stage sampling ٭ Two Stage sampling ٭ Probability Proportional to Size sampling ٭ Systematic sampling

3. Stratified Sampling  The Stratum adopted for the survey are the 4 Statistical Regions which make up Samoa ٭ Apia Urban Area ٭ North West Upolu ٭ Rest of Upolu ٭ Savaii

4. Two Stage Sampling  The two stages of the survey are as follows Stage 1 Selection of enumeration areas Stage 2 Selection of households within the selected enumeration areas

5. Probability Proportional to Size Sampling  For the first stage the EA’s are selected based on their size  The size measure is the number of h/h’s in EA according to the frame  An EA with 100h/h’s will therefore have as much chance of selection as an EA with 50h/h’s

6. Systematic Sampling  The second stage of selection, the households are selected using Systematic skip

7. The Cluster Size  An early question to address in setting up the Framework is to determining how many households do we need to select per selected EA  This is commonly referred to as the cluster size  This is generally determined at the stratum level

8. The Cluster Size (cont)  For Samoa, no technical work was undertaken to determine the most optimal cluster size.  Instead we plagiarized results from other countries  This resulted in a cluster size for each region of AUA – 5 NWU – 10 ROU – 10 SAVAII - 10

9. How many H/hs do we Select ? Best illustrated via an example (AUA) only ● Say we desire a 10% sample ● Total H/hs in AUA = 5182 (census06) ● This mean for AUA, we need a Sample size of (10/100)*5182=518 h/hs

10. Selecting the Villages and EAs Step1 Step1 Order villages by their geographical location within each Region Order villages by their geographical location within each Region Step 2 Step 2 Attach the total EAs for each village as well as the the total households for each EAs Step 3 Step 3 Convert the count of h/hs to the number of clusters by dividing the total h/h by cluster size for each Region. Eg (AUA=5) Step 4 Step 4 Calculate the Cumulative number of clusters and add to the list for each Region

11. Selecting the Villages and EAs (cont) Step 5 Step 5 Determine the skip to be run through the list for each Region =(total #clusters in each region)/(selections for the region) Step 6 Select a Random Start between the value of the skip and 0 Step 7 Produce the remaining selections numbers by continuously adding the Skip to the random start until you reach the total number of clusters in the stratum Step 8 To determine the selected villages, locate the village with the lowest cumulative # clusters value which is higher than the selection number Note: At the same time the EAs is also selected (NB: there may be 2 or more selections from village)

12. Selecting the Households  On the household list of the selected village and EAs assign a cluster number to each h/h according to the Cluster Size  Continue until the number of the clusters has been reach and then start at 1 again and repeat the process

13. Selecting the Cluster  To determined which h/h or cluster to be selected, Subtract the selection number from the previous Cumulative number.  Household list Household list Household list

14. For Excel file For Excel file

15. 1999 Census of Agriculture Framework Framework

16. FAAFETAI LAVA !!!