Editing Survey methodology (section)

==Nonresponse reduction==
The following ways have been recommended for reducing nonresponse<ref name="Lyn2">Lynn, P. (2008) "The problem of non-response", chapter 3, 35-55, in ''International Handbook of Survey Methodology'' (ed.s [[Edith de Leeuw]], [[Joop Hox]] & [[Don A. Dillman]]). Erlbaum. {{ISBN|0-8058-5753-2}}</ref> in telephone and face-to-face surveys:<ref name=Dill>Dillman, D.A. (1978) ''Mail and telephone surveys: The total design method''. Wiley. {{ISBN|0-471-21555-4}}</ref>
* Advance letter. A short letter is sent in advance to inform the sampled respondents about the upcoming survey. The style of the letter should be personalized but not overdone. First, it announces that a phone call will be made, or an interviewer wants to make an appointment to do the survey face-to-face. Second, the research topic will be described.  Last, it allows both an expression of the surveyor's appreciation of cooperation and an opening to ask questions on the survey.
* Training. The interviewers are thoroughly trained in how to ask respondents questions, how to work with computers and making schedules for callbacks to respondents who were not reached.
* Short introduction. The interviewer should always start with a short introduction about him or herself. She/he should give her name, the institute she is working for, the length of the interview and goal of the interview. Also it can be useful to make clear that you are not selling anything: this has been shown to lead to a slightly higher responding rate.<ref>[[Edith de Leeuw|De Leeuw, E.D.]] (2001). "I am not selling anything: Experiments in telephone introductions". ''Kwantitatieve Methoden'', 22, 41–48.</ref>
* Respondent-friendly survey questionnaire. The questions asked must be clear, non-offensive and easy to respond to for the subjects under study.

Brevity is also often cited as increasing response rate.  A 1996 literature review found mixed evidence to support this claim for both written and verbal surveys, concluding that other factors may often be more important.<ref>{{cite journal|title=The effect of questionnaire length on response rates -- a review of the literature|url=https://www.census.gov/srd/papers/pdf/kb9601.pdf|journal=Proceedings of the Section on Survey Research Methods|publisher=American Statistical Association|access-date=2013-03-19|pages=1020–1025|last=Bogen|first=Karen|year=1996 |url-status=dead |archive-url=https://web.archive.org/web/20130402014430/https://www.census.gov/srd/papers/pdf/kb9601.pdf |archive-date=Apr 2, 2013 }}</ref>
A 2010 study looking at 100,000 online surveys found response rate dropped by about 3% at 10 questions and about 6% at 20 questions, with drop-off slowing (for example, only 10% reduction at 40 questions).<ref>{{cite web|url=https://www.surveymonkey.com/curiosity/survey_questions_and_completion_rates/|access-date=2017-11-08|date=2010-12-10|title=Does adding one more question impact survey completion rate? |first=Brent |last=Chudoba |website=SurveyMonkey}}</ref>
Other studies showed that quality of response degraded toward the end of long surveys.<ref>{{cite news|url=http://www.research-live.com/news/news-headlines/respondent-engagement-and-survey-length-the-long-and-the-short-of-it/4002430.article |title=Respondent engagement and survey length: the long and the short of it |publisher=Research Live |date=April 7, 2010 |access-date=2013-10-03}}</ref>

Some researchers have also discussed the recipient's role or profession as a potential factor affecting how nonresponse is managed. For example, faxes are not commonly used to distribute surveys, but in a recent study were sometimes preferred by pharmacists, since they frequently receive faxed prescriptions at work but may not always have access to a generally-addressed piece of mail.<ref>{{Cite journal|last1=Agley|first1=Jon|last2=Meyerson|first2=Beth|last3=Eldridge|first3=Lori|last4=Smith|first4=Carriann|last5=Arora|first5=Prachi|last6=Richardson|first6=Chanel|last7=Miller|first7=Tara|date=February 2019|title=Just the fax, please: Updating electronic/hybrid methods for surveying pharmacists|url=https://linkinghub.elsevier.com/retrieve/pii/S1551741118309148|journal=Research in Social and Administrative Pharmacy|language=en|volume=15|issue=2|pages=226–227|doi=10.1016/j.sapharm.2018.10.028|pmid=30416040|s2cid=53281364|url-access=subscription}}</ref>