Professional survey takers also help an agency move expeditiously and achieve the necessary accuracy to assure the public that results are valid and unbiased. Informal public opinion surveys are relatively inexpensive. They can be prepared by agency staff and administered at meetings or as part of a document. But they can be useful. Scientific surveys are expensive because of the complexity of drawing a sample population or structuring the questions asked.
Time is also a significant factor because of survey preparation and administration.
Collecting, transcribing, and summarizing data becomes increasingly expensive as the number of questions or size of the sample increases. A carefully-selected sample reflecting many types of interests within the larger population takes additional time and money. An agency ascertains the need for information and then determines the most appropriate means of getting it. If an agency needs opinions about a planning effort or project that is getting underway, for instance, it needs to determine whether formal or informal comments are most appropriate. An agency determines the types of questions to be asked.