ncompass live: conducting surveys ii: data collection
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TRANSCRIPT
Conducting Surveys II
Data Collection
NCompass Live – June 9, 2010
About you
Your role
Library DirectorTrusteeFriends/Foundation Board Member
Your credentials
About you, cont’d
About you, cont’d
Recap of Conducting Surveys I
Reasons for conducting a surveyIssues in effective questionnaire design, data collection and analysis, and reportingQuestionnaire design, especially measurement, content, and structure
About this presentation
SamplingHow to target your respondentsSurvey methods
Sample
A subset of individuals within a population of interestSampling is the act, process, or technique of selecting a suitable sample, or a representative part of a population for the purpose of determining parameters or characteristics of the whole populationGoal of sampling: to be able to make inferences to the population in question
Why sample?
Lower costFaster data collection
Sampling process
Defining the population of concernSpecifying a sampling frame, a set of items or events possible to measureSpecifying a sampling method for selecting items or events from the frameDetermining the sample sizeImplementing the sampling planSampling and data collectingReviewing the sampling process
Define the population
Definition: Entire universe of individuals who have characteristic of interest
Examples: Residents of city, residents of county, library card holders, users, nonusers, visitors to library, computer lab users, program attendees
Sampling frame
Definition: has a property that we can identify and can include in our sample
Examples: telephone directory, city directory, patron database, attendance sheets, voter registration list, utility bill recipients, newspaper readers, random digit dialing (RDD)
Sampling methods
Probability sampling: every individual has an equal chance of being selected
Nonprobability sampling: some units in the population have no chance of selection or the probability of selection can’t be accurately determined
Sampling methods examples
Probability
Simple randomSystematicStratified
Nonprobability
ConvenienceJudgmentQuotaSnowball
Sampling example #1
Simple randomPopulation: PatronsFrame: Patron databaseMethod: Random number generator—in Excel: =RANDBETWEEN(num1,num2)
Sampling example #2
SystematicPopulation: City residents that have a listed land-line telephoneFrame: Telephone directoryMethod: Randomly select a number n (ex., 20) or smaller, start there on the first page of the directory and select every nth (ex., 20th) entry
Sampling example #3
ConveniencePopulation: Library visitorsFrame: Anyone who approaches or passes by the reference deskMethod: Stop as many people as possible
Population example
Entire universePopulation: Event attendeesDistribute questionnaire to everyone in attendance
Sample size criteria
Level of precision/sampling error (e.g., ±5 percent): range in which the true value of the population is estimated to beConfidence level: repeat sample values are normally distributed about the true valueDegree of variability: heterogeneous populations require a larger sample size
Determine sample size
(Obtained responses) Table 1. Sample size for ±3%, ±5%, ±7% and ±10% Precision Levels Where Confidence Level is 95% and
P=.5.
Size of Sample Size (n) for Precision (e) of:
Population ±3% ±5% ±7% ±10%
500 a 222 145 83
600 a 240 152 86
700 a 255 158 88
800 a 267 163 89
900 a 277 166 90
1,000 a 286 169 91
2,000 714 333 185 95
3,000 811 353 191 97
4,000 870 364 194 98
5,000 909 370 196 98
6,000 938 375 197 98
7,000 959 378 198 99
8,000 976 381 199 99
9,000 989 383 200 99
10,000 1,000 385 200 99
15,000 1,034 390 201 99
20,000 1,053 392 204 100
25,000 1,064 394 204 100
50,000 1,087 397 204 100
100,000 1,099 398 204 100
>100,000 1,111 400 204 100
a = Assumption of normal population is poor (Yamane, 1967). The entire population should be sampled.
Table 2. Sample size for ±5%, ±7% and ±10% Precision Levels
Where Confidence Level is 95% and P=.5.
Size of Sample Size (n) for Precision (e) of:
Population ±5% ±7% ±10%
100 81 67 51
125 96 78 56
150 110 86 61
175 122 94 64
200 134 101 67
225 144 107 70
250 154 112 72
275 163 117 74
300 172 121 76
325 180 125 77
350 187 129 78
375 194 132 80
400 201 135 81
425 207 138 82
450 212 140 82
Implement the sampling plan
Evaluate the sample
Response rate
Number completedTotal number in
sample
Survey methods
QuestionnaireMail, paper-and-pencilGroup-administeredInternetE-mail
InterviewPersonalTelephone
Targeting your respondents
MailE-mailWebsiteNewsletterPress release
Method of administration
Paper-and-pencil (Self report, face-to-face, telephone)Electronic (e-mail)Online/Internet
Pros/cons
Paper-and-pencil
Self reportFace-to-faceTelephone
Online
SurveyMonkey– https://www.surveymonkey.com/
Zoomerang– http://www.zoomerang.com/
FreeOnlineSurveys.com– http://freeonlinesurveys.com/
Polldaddy– http://polldaddy.com/
LimeSurvey– http://www.limesurvey.org/
SurveyGizmo– http://www.surveygizmo.com/
twtsurvey– http://twtpoll.com/new.php?op=2
Data collection walkthrough
Paper-and-pencilOnline
Resources
Survey Research Methods, 4th Ed., by Floyd Fowlerhttp://www.statpac.com/surveys/sampling.htm http://www2.uiah.fi/projects/metodi/152.htm http://www.socialresearchmethods.net/kb/sampling.phphttp://nelearns.blogspot.com/2010/05/thing-37-engaging-your-users-with-polls.html http://www.techsoup.org/learningcenter/software/page10744.cfm http://www.techsoup.org/learningcenter/internet/page5048.cfm
Next steps
Evaluation
Questions?
Evaluation
CE credits
Related topics
NCompass Live archived sessions
Conducting Surveys I: Introduction and Questionnaire Design – May 12, 2010http://www.nlc.state.ne.us/scripts/training/eventshow.asp?ProgID=9680
Presenting Data in Meaningful and Interesting Ways – Jan. 1, 2010http://www.nlc.state.ne.us/scripts/training/eventshow.asp?ProgID=9338
American Factfinder - Mining the U.S. Census for Information about Your Community – Dec. 9, 2009http://www.nlc.state.ne.us/scripts/training/eventshow.asp?ProgID=9297
Upcoming sessions
Tech Talk with Michael Sauers – June 30http://www.nlc.state.ne.us/scripts/training/eventshow.asp?ProgID=9639
Conducting Surveys III: Analyzing Data and Reporting Methods – July 14http://www.nlc.state.ne.us/scripts/training/eventshow.asp?ProgID=9638
Communication--Getting the Word Out: Does your audience hear what you mean? – July 21http://www.nlc.state.ne.us/scripts/training/eventshow.asp?ProgID=9238
Resources
Survey Research Methods, 4th Ed., by Floyd Fowlerhttp://www.statpac.com/surveys/sampling.htm http://www2.uiah.fi/projects/metodi/152.htm http://www.socialresearchmethods.net/kb/sampling.phphttp://nelearns.blogspot.com/2010/05/thing-37-engaging-your-users-with-polls.html http://www.techsoup.org/learningcenter/software/page10744.cfm http://www.techsoup.org/learningcenter/internet/page5048.cfm
Your feedback
http://www.surveymonkey.com/s/82PKWYH
Thank you!