 Questionnaire data can be "pre-coded" (process of assigning codes to expected answers on designed questionnaire), "field-coded" (process of assigning codes as soon as data is available, usually during fieldwork), "post-coded" (coding of open questions on completed questionnaires) or "office-coded" (done after fieldwork).Note that some of the above are not mutually exclusive.In social sciences, spreadsheets such as Excel and more advanced software packages such as R, Matlab, PSPP/SPSS, DAP/SAS, MiniTab and Stata are often used.