Presentation on theme: "Survey Experiment Modalities Some Pros and Cons of Differing Sampling Sources and Methods Matthew A. Baum Harvard University & Leonie Huddy Stonybrook."— Presentation transcript:
Survey Experiment Modalities Some Pros and Cons of Differing Sampling Sources and Methods Matthew A. Baum Harvard University & Leonie Huddy Stonybrook University
Outline Review of prominent Internet players Amazon Mechanical Turk Knowledge Networks Yougov/Polimetrix SurveyMonkey Audience Comparing survey modalities USA vs. Swedish Phone/Internet Usage Statistics Conclusions
Amazon Mechanical Turk (AMT) Overview Began in 2005 “Workers” sign up to participate in tasks for pay (called “Human Intelligence Tasks”, or “HITs”) Global workforce (~100,000 workers) Salary: ~$3-$8/hour (maybe $10/hr for high-experience workers) “Requestors recruit “workers” on internal message board describing task Can specify “qualifications” for workers (e.g., experience, quality ratings, nationality, etc.) 10% fee to Amazon AMT provides survey building tools, or Requestors can include links to external surveys HITs range from 1-second marketing surveys (“Rate appeal of this photo on 1-10 scale”) to elaborate 30+ minute experimental surveys
Compensation Amount Short survey (5 min) Medium survey (10 min) Long survey (30 min) $ $ $ Effects of Compensation Amount and Task Length on Participation Rates (Submitted Surveys per Hour of Posting Time) Source: Buhrmester, Kwang, and Gosling (2011) My AMT Experience: paid $1.00 per completed HIT for ~22 minute survey Listed as “News and Politics Survey” Received 1933 completed surveys in ~one month rapidly diminishing returns 1825 valid responses Amazon Mechanical Turk (AMT)
% Female% Non- White % Non- American Age AMT Internet57Fewer (?)~ Buhrmester, Kwang, and Gosling (2011) Amazon Mechanical Turk (AMT) Demographics Paolacci, Chandler, and Ipeirotis (2010) Category(N=1000 AMT workers) % Female64.9 Average Age36 % Earning below $60k/year66.7 Education“higher than general pop.” % Non-American53
Amazon Mechanical Turk (AMT) My AMT Survey (N=1824) US National Averages (From Pew 2010 Survey) Average Age % Non-White % Female % Democrats % Republicans % Independents % Liberal % Moderate % Conservative Demographics
Amazon Mechanical Turk (AMT)
Follow-Up Survey Contacted all 1825 workers who completed valid HITs in original survey approximately 4 months later Offered $.50 for ~12 minute survey 426 valid responses (24%) 2 nd batch of invites
Some Conclusions re AMT “Our analyses of demographic characteristics suggest that MTurk participants are at least as diverse and more representative of noncollege populations than those of typical Internet and traditional samples. Most important, we found that the quality of data provided by MTurk met or exceeded the psychometric standards associated with published research.” Buhrmester et al. (2011) “Our theoretical discussion and empirical findings suggest that experimenters should consider Mechanical Turk as a viable alternative for data collection.” Paolacci et al. (2010)
Knowledge Networks 2007 Survey (via TESS) Participants recruited via residential address searches Respond online (Internet access provided to recruits who don’t have it) Pretty good samples, but imperfect (selection effects not completely purged) and expensive Demographics Post-Survey Matched Sample(N=1014) % Female50 % Non-white26.7 % Liberal25 % Moderate41 % Conservative33 Average Age46 Ideological Intensity (0-3 scale).99 Political Knowledge (0-1 scale).487
Recent (2012) KN Proposal Design: 4-wave study, longitudinal sample, all waves occurring within 1 yearDesign: 4-wave study, longitudinal sample, all waves occurring within 1 year Pretest: N=25 interviews each wavePretest: N=25 interviews each wave Sample: General population adults, age 18+, English-language survey-takersSample: General population adults, age 18+, English-language survey-takers Number of completed interviews: N=2,000 wave 1, with about 70%-80% of wave 1 respondents completing each of the later wavesNumber of completed interviews: N=2,000 wave 1, with about 70%-80% of wave 1 respondents completing each of the later waves Median survey length: 20 minutes each waveMedian survey length: 20 minutes each wave Multimedia/graphics: NoneMultimedia/graphics: None Incentives: $5 for each of waves 1-3, $10 for wave 4Incentives: $5 for each of waves 1-3, $10 for wave 4 KN will provide standard deliverables (self-documented data file with all the survey data, general demographic profile data, and field report documenting all sampling and data collection procedures, codebook, and panel recruitment methodology)KN will provide standard deliverables (self-documented data file with all the survey data, general demographic profile data, and field report documenting all sampling and data collection procedures, codebook, and panel recruitment methodology) Price: $255,550 (No, that’s not a typo!) Price: $255,550 (No, that’s not a typo!)
Yougov/Polimetrix Opt-in sampling Random draw from target population matched with most comparable available panelists to create representative population samples Demographics + attitudinal/behavioral factors Post-Survey Matched Sample My Survey (2007, N=1200) CCAP (2008, 6-wave panel)* Average Age % Female5152 % Non-white % Democrat % Republican % Independent % Liberal % Moderate % Conservative *Notes: (1)Overweights battleground states 2-fold. (2)Demo weights based on age, race, gender, educ, marital status, kids, income, state, metro area, employment, citizenship (3)Attitude/Behavior weights based on religion, church attendance, evangelical status, news interest, PID, ideology.
Comparing Modalities: KN vs. Polimetrix vs. Natural Survey: Barabas & Jerit (2010)
Polimetrix vs. Pew vs. NES (Partisan Distribution) Source: Hill, Lo Vavreck & Zaller (2007)
Polimetrix vs. Pew vs. NES (Ideologial Distribution) Source: Hill, Lo Vavreck & Zaller (2007)
Demographic Comparisons Source: Hill, Lo Vavreck & Zaller (2007)
Comparing Modalities: KN vs. Polimetrix vs. Natural Survey: Barabas & Jerit (2010) Conclusions: “The results presented here should be encouraging to anyone devoted to the scientific study of politics because they suggest that what occurs in survey experiments resembles what takes place in the real world.” “Although there was a discrepancy between the size of survey treatment effects and the general population in our natural experiment, we observed correspondence exactly where one would expect to find it—among those who were most likely to be exposed to media messages about the two government announcements.”
SurveyMonkey Audience New enterprise for SM still figuring it out! Recruit participants from survey respondents Currently U.S. only, but likely to expand $3 per finished response; $5 for rush project (3 business days) Custom create demographic profiles Gender, age, income, location, education, race, industry of employment, job function, marital status, employment status, home ownership, vehicle ownership, smartphone ownership, exercise habits. No political attitude selectors yet (though I’ve lobbied them!) Similar to Polimetrix, except don’t start with random draw from population Much less expensive!
AAPOR 2010 Task Force on Online Panels Focus on nonprobability samples Informative, but inconclusive… Conclusions If research objective includes accurate estimate of population values, avoid nonprobability online panels. Results differ significantly from probability-based methods (like RDD telephone) on range of behaviors and attitudes, with latter being more accurate. Nonprobability online panels sometimes appropriate, when precise estimates of population values not critical More research needed on evaluating and testing techniques used across disciplines to make population inferences from nonprobability samples.
Ansolabehere & Schaffner (2011) Comparison of Survey Modalities 3-mode study conducted in Opt-in Internet panel 2.Live telephone interviews (using national RDD sample of landlines and cell phones) 3.Mail (using national sample of residential addresses)
ModeSample Size Field DatesResponse Rate Completion Time Internet10001/15/10-2/11/1042.9% (RR1)8.94 mins Mail12071/30/10-9/30/1021.1% (RR3)11.80 mins* Phone9071/28/10-1/30/1019.5% (RR3)14.33 mins Ansolabehere & Schaffner (2011) *mail recruits who took survey online
Ansolabehere & Schaffner (2011) ItemResponseInternetPhon Validating Source Home Ownership Own (CPS) MobilityMoved in past year At address 5+ years (ACS).588 (ACS) Smoked 100 Cigarettes Yes (NHIS) Smoke Cigarettes now Every or some days (NHIS) Voted in ‘08 (if registered) Yes (CPS) Vote Choice in ‘08 Obama McCain Avg Diff
Non-validatable Political Point Estimate Comparison, by Mode Includes State of Economy, Approval of/Support for Obama, Congress, R’s Member, Abortion, Affirmative Action, Gay Marriage, Investing Social Security, Tax over $200k, Cut Spending, Government Right and Wrong Voting Method Religious and/or Political Contributions Political Knowledge News Source Ansolabehere & Schaffner (2011) Internet vs. Phone Phone vs. Mail Internet vs. Mail Avg Diff. (All measures) Avg Diff. (Attitudinal measures only) Weighted proportions of respondents in each category, excluding DK.
Small (“negligible”) differences across modes Except…Internet respondents more politically knowledgeable & made more political contributions Mail costs 5 times more than Internet & twice as much as phone Internet half as costly as phone and faster turnaround Differences from other studies that found Internet samples less valid than phone samples attributed to (1) more Internet users than 5+ years ago when prior data samples collected, and (2) advances in “science of constructing, matching and weighting opt-in Internet panels” Conclusion: “...an opt-in Internet survey produced by a respected firm can produce results that are as accurate as those generated by a quality telephone poll and that these modes will produce few, if any, differences in the types of conclusions researchers and practitioners will draw in the realm of American public opinion.” Ansolabehere & Schaffner (2011)
U.S. Telephone Ownership Media Access, Sweden vs. USA
Swedish Phone Use by Age Source: Axelsson (2010)
Why Persistent Mobile Phone & Internet Usage Gaps? Income Inequality: USA vs. Sweden in 2011
Effects of Income on Internet Usage in U.S. U.S. has more of these folks
What Do Data Tell Us? Swedes more likely to be online in 2010 (by ~14 percentage points), and make greater use of Internet But, similar in fixed broadband and landline usage More likely to use mobile phones But similar in volume of mobile calls sent and received Moral of story? Infrastructure looks, if anything, LESS hospitable to probability sampling in Sweden than in USA So, if RDD today works better in Sweden for generating probability samples, reason seems likely to have more to do with attitudes toward surveys than infrastructure
Conclusions Opt-in Internet samples here to stay Cheaper (by a lot!) Faster (by a fair amount…) Primary competitor (RDD phone surveys) increasingly difficult 14% of adults “unreachable” in Sweden? Estimated 25% of U.S. households cell only in “Unreachable”: ~13% (AAPOR 2010); others say more Open up new possibilities E.g., cross-national samples/panels Most current evidence suggests that with current matching and weighting techniques, Opt-in Internet samples can be representative of target populations