The phrase 'main survey' is correct and can be used in written English.
For example: "The main survey was conducted among 200 people in the city."
The other main survey firm, Ibope, reported a gap of six percentage points.
The interviewers successfully reached every district and completed the main survey in one month May 20133).
Household occupants were generally willing to participate in the main survey, conducted at home.
The main survey included 5,041 households at which the interviewers called unannounced.
More details about the ANC survey are available in the main survey report [11].
To ensure quality of data collected, independent teams spot-checked households randomly within three days of the main survey.
Research relating to the main survey data is planned.
So, 55 references (73%) were part of the main survey.
The modified instrument was used for the main survey.
The main survey was then conducted in September 2012.
The response rate for the main survey was 62%.
