1. 4. Creating an Extract (9 slides)

2. 4. Creating an extract » Password protected: to make and retrieve extracts » Licensed researcher selects: » Countries, » Censuses, » Cases/sub-populations, » Variables, and » Sample densities » Extract engine queues request, generates extract » Researcher retrieves extract via web with SSL 128-bit encryption and analyzes using own wares (soft/hard/wet) » NO: CDs, original codes, or complete datasets

3. 2b. “Create an Extract”

4. 4 steps in creating an extract (the database is huge—the key is “extracts”): 0. Login with your email and password

5. 1. Select countries & census years

6. 2. Select variables “case selection” (Selection of cases (subpoblations)

7. 3. Selecting cases

8. 4. Downloading the extract

9. Analyze with your preferred statistical package » “Un-ZIP” with “WinZIP; careful with Windows folders » Apply weights (WTPER; note 4 decimals!): » Essential for countries like Brazil, Mexico, Spain, USA, etc. but not Greece » Expansion factors: households (WTHH) or persons (WTPER) » Derivation of weights: WT=WT/mean(WT, each sample), HH or PER *SPSS Instructions for expansion factors. COMPUTE wtper = wtper/10000. [Note 4 decimals!!!!!] WEIGHT BY wtper. *….. To weight cases, yet maintain the actual number of cases in the sample, consider, for example Brazil: COMPUTE wtcensus=census. RECODE wtcensus (96 97 98 = 20) (99=17.24) (00=16.67) [“96” = 1960, 97=1970]. COMPUTE wtper=wtper/wtcensus. WEIGHT BY wtper.