(See https://meta.wikimedia.org/wiki/Research:Wikipedia_Editor_Survey_2012  for general information about this survey)

In order to preserve the identity and privacy of the editing community, we have made several modifications to the dataset.
1.        First off, we removed all the open-ended responses from the data. For instance, the text portions of all the “Other, please specify:” sections associated with some questions (one example: “If you had to name one thing that motivates you most to contribute to Wikipedia, what would it be?”) were removed from the data.
2.        For the purposes of our analysis, we had included actual user data: lifetime edits, joining year, whether the user is an admin or reviewer on the wiki where they started the survey etc. This was excluded from the dataset. We retained the project name of the wiki where the user started the survey (e.g. “frwiki” for the French Wikipedia).
3.        Also, we removed the columns describing the response's start date, end date, response set, and status, as it wasn’t relevant.

After these basic checks, we took a series of steps to ensure the privacy of minorities – geographic, language as well as gender. Due to their relatively smaller numbers, we wanted to make sure that their identities could not be easily deciphered.
For Country of residence (D5), the primary languages question (D7), the Wikipedia contribution languages questions (Q1a, Q1b), as well as the reading languages questions (Q2a, Q2b) and the project name:
a.        If the total number of entries for a single response (for instance, a single country) was less than 26, all those entries were set to “other”.
b.        Next, if the number of entries by women were less than 11, all those entries were set to “other”.
c.        Due to their extremely small numbers, responses to these questions given by transsexuals and transgenders were set to “other”.

For country-specific datasets (prepared for those countries of residence with >100 respondents in D5 that had been removed in step 3 - Austria, Brazil, Switzerland, Colombia, and Indonesia):
1. Remove the gender response column entirely
2. Go through all of the steps above (without 3a and 3b, of course), with the limit of 26 in 3a referring to the number of responses from that particular country
3. Remove the response ID to avoid re-matching with the general anonymized dataset
4. Randomize order of rows