Data Processing
Data Cleaning
During the field stage, field editors and INE technical supervisors checked for data inconsistencies in the field and during data entry. The questionnaire included some coding for geographic reference, and once ballots were filled out, field editors checked coding was appropriately done by interviewers and also coded economic activities. Corrections were done manually by visual control of the questionnaire and no software was used.
Data Entry Process
Data entry was conducted manually by 11 data-entry clerks from March 14 through April 13, 2011 (two rounds of data entry). All data was entered at INE's data processing department using manual data entry. Clerks entered data using 11 desktop computers using a CSPro template developed by the National Statistics Institute (INE), following the HH-survey questionnaire model. Once data was entered, they were validated using CSPro to identify coding and continuous variables inconsistencies (i.e. values outside certain number of standard deviations, non-logical values, etc.), false skips and any other discrepancy from the questionnaire-model programming. All range checks and skips were controlled by the program and data-entry clerks could not override these. Most open-ended responses ("Other" answers) were not entered or coded, except in rare circumstances where the response matched an existing code in the questionnaire.
Double data entry was conducted on 100% of ballots to perform independent verification of all variables. This process also included separate comparison of data followed by modification of one or both datasets to correct keying errors by original operators who first keyed the files.
After verifying inconcistencies and and incorrect values, mistaken-data depuration took place between 5.04.11 and 5.12.11, and was conducted in SPSS
Documentation in PDF