Methods of Data Collection and Mode of Administration

IntroductionMethods of Data Collection andMode of Administration• Introduction: Defining method or mode of data collection*• Choice of mode*• Comparisons across modes• Effects of mode• Advantages and disadvantages of modes**These sections based on JPSM materialsThe evolution of survey technology*Methods of data collection and modes ofadministrationPaperMailTelephoneFTFComputerOCR/ICR FAXCSAQ MethodsDisk-by-mail E-mail WebCATI TDE IVR/T-ACASICAPI CAI Methods• For the first several decades of survey research, “mode” meant one of thefollowing• Face-to-face or personal visit survey• Telephone survey• Mail survey• More ways of collecting data are now available and they are combined inmany ways• Now we need to distinguish among the different tasks that technology(including paper, telephones, mail) performs in our surveysSAQText-CASIAudio-CASIVideo-CASIWalkman8

Definition• Method of data collection or mode of administration sometimes refer to• Method for contacting sample member• In-person, telephone, mail, internet• Means by which question is administered to respondent• Interviewer, other aural, text• Medium on which response is recorded• Paper, computer• Method and mode are also closely associated with sample framePrincipal modes of administering questions andrecording responsesQuestionAdministrationInterviewer(IAQ)Interviewer(IAQ)Voice andtextFace-tofaceRecordingResponsesPaperPAPITelephone PATIComputer(CAI,CASIC)CAPICATIA-CASIText SAQ CASIP Mixed mode surveys may combine more than one means of delivery or morethan one means of question administration or responseP Other modes – TDE, direct to disk, web-based surveys, etc. – have beenstudied less.Computer-assisted survey information collection(CASIC) or Computer-assisted interviewing (CAI)• Technologies that are available change rapidly• Task performed by technology include• Manage sample• Present survey questions• Record answers• Edit data• Exchange dataImplications of the proliferation of methods andmodes• Need to ask what reference to mode refers to and to be explicit in yourown work• Research about method or mode effects• Need to be explicit about what “mode effect” refers to (e.g., frame,method of contact, method of administration)• Literature does not (yet) cover all variations• Need theory to inform expectations about effects• Mixed-mode surveys or hybrid designs• Increasingly common• Effect of mode may depend on the particular combination of methodsused• Designs to test effects increasingly difficult to design and interpret• Hard to generalize about mode comparisons

Choosing method of data collection:Considerations• Survey population: Characteristics, abilities, resources, andinterests• Sample frame: Information available in sample frame (area,name, address, telephone number)• Sample design: Clustering, stratification, selection of respondent• Study topic: Sensitivity, task difficulty, need to use visual aids• Analytic goals: Comparisons needed with studies using othermodes• Interviewer corps: Ability and experience• Response rate: Need for high response rate• Administrative infrastructure: Availability of technology andexperience with technology• Cost: Desired length of field period• Cost: Other considerationsChoosing method of data collection (continued)• Impact of mode on error• Sampling error• Coverage error• Nonresponse error• Measurement error• Comments:• Decisions about error require consideration of time and budgetconstraints and trade-offs• There is no one best mode for all situationsChoice of mode: Frame• Three basic types of frames: area, telephone, and list• Area frame: no list of addresses or persons in U.S., so usegeographic/political units as frame• Telephone: Most designs now are list-assisted RDD, and increasinglyhave dual-frame designs with cell phones• Mail: Addressed-based sampling (ABS) provide frame for mail surveysof household• List: lists vary in the amount and quality of information in the frameand what modes they can support• Information in frame and survey design• Frames vary in coverage of target population• Information in frame determines how sample unit can be contactedand how survey instruments can be distributed• If frame includes address, design can include advance letters,prepaid incentives, etc., regardless of mode• Some frames provide ability to subsample within sample clusters onthe frame (e.g., within households)• Frames vary in coverage of target populationChoice of mode: Coverage and other problems insampling frames• Typical frames differ in how well they cover target population• Frames may provide information for assessing or determining eligibilityof units on the frame (e.g., administrative record in frame based onobservation of or self-report from sample unit)• All designs that involve selecting respondents share coverage errors dueto measurement errors made by respondent (e.g., for number ofpersons in household, last birthday, etc.)

Choice of mode: Coverage and other problems insampling frames• Area probability frames• In principle could include all, in practice include those in sampling units(e.g., households)• Coverage error due to listing errors by interviewers• Coverage errors may be reduced by use of address lists• List-assisted telephone frames (RDD)• Exclude those without telephones• Exclude with only cell phones unless use a dual-frame design• Those with only cell phones more likely to be young, poor, andrenters• Duplicates both within and across landline and cell phone frames• Address-based samples• Potentially excellent coverage• Quality may be poorer in rural areas or areas with delivery to mailboxestnrceeP70.060.050.040.030.020.010.00.0US Households withComputer and Internet Access (CPS)..1984..1989 ..1993..1997 ..2000..2001 ..2003..2007ComputerInternetU.S. Households with Computers, by Income*1009080706050403020100All

Comparison of address-based sampling (ABS)and RDD (Link et al. 2008)Choice of Mode: Sampling error• Clustering• Increases sampling variance, but reduces costs• Less clustering is needed in telephone than face-to-face surveys• Maximum dispersion possible in self-administered methods based onlist (address) sample• Sample size• Cheaper modes make larger sample size possible for a given budget• XMethod of data collection: Nonresponse• Methods vary in• Rates of nonresponse• Sources of nonresponse• Types of nonresponse• Noncontact: Access restrictions vary by method• Telephone: Caller-ID, answering machines• Face-to-face: Gated communities, locked apartment buildings• Mail: Difficult to distinguish ineligible, non-contact, and refusals• Web: Access to web and spam filters• Refusals: Willingness to cooperate may depend on method of contact• Mail: Limited to written materials and incentives• Interviewers: Potential ability to tailor responses to respondent’sconcerns• Respondents vary in ability to use different methods• Mail and self-administered: Literacy• Computer-assisted: Comfort with technology• Web: Access to webNonresponse: Mail• Rogers (1989):• average of 20.2 pieces of mail received per week• 42% increase in mail received over 10 years• 200% increase in 3rd class mail• Mathiowetz, Couper and Singer (1994):• systematic variation in amount of mail received by income, urbanicity,race• in 63% of households, 1 person responsible for opening mail• 63% of households throw some mail away without opening• modest association with census mail return, controlling on other factors

Nonresponse: MailNational Assessment of Adult Literacy (2003)• Conducted in 2003, over 19,000 adults participated in the national andstate-level assessments, representing the entire population of U.S. adultswho are age 16 and older, most in their homes and some in prisons fromthe 50 states and the District of Columbia. (http://nces.ed.gov/naal/)Choice of mode: Measurement process• How data collector or interviewer is involved• Interviewer administers questions• Interviewer present during self-administration• Self-administration without interviewer present• The type of contact between interviewer and respondent• Co-present, physical and social: face-to-face• Co-present, social: telephone• Indirect presence: mail or web• None: direct observation, administrative recordsChoice of mode: Measurement process(continued)• Channels of communication used to present questions• Aural only (example:Telephone survey with no visual aids)• Aural + visual (example: Face-to-face with show cards )• Visual only (example: Mail SAQ, CASI)• Visual on a screen may differ from visual on paper• Visual can include only text or text and pictures• Type of technology used to record answer• Paper: mail, paper-based methods• Electronic technology:• Data collector: computer-assisted interviewing• Respondent uses electronic technology supplied by surveyorganization: computer-assisted self-interviewing• Respondent uses own electronic technology: Web surveys

Choice of mode: Measurement process(continued)• Privacy, presence of others• Low privacy: exit interviews, intercept surveys, group administeredsurveys• Medium privacy: in-home interviewer-administered surveys• Medium high privacy: telephone• High privacy: laboratory-based measurementMeasurement process: Classification of modesof administration (Biemer and Lyberg 2003, Table6.1)High Data CollectorInvolvementPaperComputerLow Data CollectorInvolvementPaperComputerDirect RcontactIndirect RcontactNo RcontactFace toFace (PAPI)Telephone(PAPI)DirectObservationFace-to-Face (CAPI)CATICADEFace to face(Diary)Mail, fax,emailAdministrativeRecordsFace toFace (CASI,ACASI)TDE, email,Web, DBM,EMS, VREEDI7Mode: MeasurementMeasurement: Respondent• Mode affects all aspects of measurement process• Interviewer• Respondent• Instrument• Respondents vary in• Preference for mode• Motivation and ability to perform in different modes• Tendency to satisfice, acquiesce, give socially desirable answers• Modes vary in ability to provide respondents assistance with difficultresponse tasks

Measurement: Interviewer• Advantages and disadvantages of presence of interviewer• Presence of interviewer enables use of more complex instruments andmixed modes (e.g., audio-CASI)• Presence of interviewer may increase roh_int• Advantages of centralized telephone interviewing (compared todecentralized telephone or face-to-face)• Increases standardization and therefore reduces roh_int• Training is cheaper, can be more intensive, and be ongoing• Continuous supervision and monitoring are possible• Greater flexibility in assignment of cases• Disadvantage of centralized telephone interviewing• Without travel burden, telephone interviewers can have largerworkloads, which may lead to larger impact of rho_intMeasurement: Instrument• Length of questionnaire• Complexity of instrument• Skip patterns, branching, instructions• Alternative measurement tools and visual aids: showcards,observation, direct measures, etc.• Error checks, range checks• Question form• Open questions• Number of response alternatives• Effects on answers• Item nonresponse• Social desirability• Effects of response order• Primacy and recency• Effects of question order• Assimilation and contrastPaper vs computer• Data Quality• Little effect on unit nonresponse, item nonresponse• Timeliness• Effects on production schedule• Complexity of the survey instrument• Computer-assisted interviews can include dependentinterviewing, complex fills, complex skips• Computer-assisted instruments produce meta-data (such astiming) at little additional cost• Difficult to compare costs• Computer-assisted instruments are often more complex thanpaper• Testing and debugging• Project management may be more complex for CAIEffect of dependent interviewing on longitudinaldata• Substantial proportion of monthly industry and occupation changes inCPS found to be spurious (Collins, 1975)• 39% of those reporting no job change have different occupation code insuccessive months• 21% of those reporting no change in employer had different industrycodes• CATI/RDD test using dependent interviewing (Dippo et al., 1994)• 7% changed occupation code from month to month• 5% changed industry code from month to month

Choice of mode: Costs• Staff• Centralized telephone staff compared to field staff• Can be deployed on different studies• Fewer are needed, so hiring and initial training is moreeconomical• Can be trained and supervised more economically• Mail surveys have less complex staffing needs• Nonresponse followup: Cost of repeated contacts varies by mode• Field period: Methods differ in how quickly get into and out offield• Infrastructure: Computer-assisted methods require equipment,frequent updating, and trained staffFive different types of mixed-mode design (Groves et al.2004, p. 163; Dillman and Tarnai, 1988)• One mode for some Rs, another mode for others• e.g., telephone survey, with FTF component for those without telephones• e.g., mail survey with web response option• One mode for recruitment, another for survey administration• e.g., mail invitation for web survey• e.g., telephone recruitment for IVR survey• One mode for data collection, another for reminders or follow-up• e.g., telephone reminders for mail or web survey• One mode for one wave of a panel survey, another for others• e.g., first wave of panel is FTF, subsequent waves by telephone or mail• One mode for main part of the interview, another mode for some subset of items• e.g., audio-CASI for sensitive items• One mode for one sample frame, another mode for another sample frame; bothframes for the same population• e.g., dual-frame RDD and area probability design• Use one mode for one population and another for another population, with goalof comparing them• telephone for elites, mail for nonelitesComparisons across modes:Design factors affecting mode comparisonsSampling Frame definition and coverageSample designRespondent selection rules andproceduresNonobservation Procedures to gain initial cooperationFollowup for noncontactRefusal conversionItem nonresponseMeasurement Question technique and instrumentdesignRecording medium - paper vs computerInterviewing Experience of staffTrainingSupervision and quality controlAssignment sizeComparisons across modes: Two extremes• Hold all features of design constant and vary only means of delivery ormeans of question administration and response• Compare "typical" designs for each mode

Mode comparisons: Strategies• Panel design with second wave assigned to different modes• Use of frame with information for both modes (e.g., telephone directory,register)• Use of different frames for each mode (e.g., area sample and RDDsample)• Meta-analysis of mode comparison studiesComparisons across modes: Examples• Panel designs• Use "maximum" of one mode (e.g. face- to-face) at time 1 and ofanother mode (e.g., telephone) at time 2.• Random halves of sample assigned to different modes at time 2.• Split sample designs• Address or area frame. Obtain telephone numbers. Assign half topersonal and half to telephone.• Area frame for face-to-face interviews. Independent sample fromtelephone exchanges for telephone.Mail vs face-to-face surveys (Krysan, Schuman, Scott andBeatty 1994)Face-to-FaceMail1992 DAS 1992 DASArea probability,oversample from stratumwith high proportion blackAdult randomly selected byinterviewersOne hour interview(220-300 questions)Pen in advance as giftAddresses selected fromDAS frame, but nooversample frompredominantly blackstratumAdult with most recentbirthdayApproximately 10 minutequestionnaire$1 with questionnaireResponse rates by mode of administration and racialcomposition of the strata (Krysan et al. 1994, Table 1)Predominantly WhiteStratumMail(a)Face-to-face(b)Predominantly BlackStratumMail(c)Face-to-face(d)Response rate 74 75 46 83N 476 1,037 84 512Significant comparisons: d vs c, a vs c, b vs cP Results for predominantly black stratum confound race,education, income, and urban residence.P In calculating response rates for mail survey,nonrespondents include addresses with no completedquex or for which postal service did not return the quex asundeliverable

Sample and nonsample addresses by mode ofadministration and racial composition of the strata(Krysan et al 1994, Table 2)PredominantlyWhite StratumMail(a)Face-to-face(b)PredominantlyBlack StratumMail(c)Face-to-face(d)Sample addresses 94 96 88 89Nonsample addresses 6 4 12 11Vacant houses 3 4 6 10No eligible respondent ...

Effects of mode: Participation• Sample frame and design• information about sample unit• method for selecting respondent• screening• Initial approach• advance letter• show of credentials• demonstration of "harmless" presence, legitimacy• Followup• mode and staffing of followup contacts• availability of mixed mode contacts• Respondent preference• Comment: Modes differ in which interpersonal norms are activated andprovide motivation for participation. Mode may affect who participates aswell as how many participateEffect of mode on participation: Comparison offace-to-face and telephonePercent CompleteFaceto-faceTelephoneHochstim (1967:979) 93 91Groves( 1979: 192) 74 59-70Jordan et al. (1980: 212) 64 49Sykes and Collins (1988) 606867de Leeuw & van derZouwen (1988:288)53464575 69Effect of mode on participation: Metaanalysisof 45 studies (Hox and de Leeuw1994)P face-to-face 70%P telephone 67%P mail 61%Effects of mode: Item nonresponseStudy Question FTF vs PhoneGroves andKahn(1979:195)Jordan et al.(1980:212-16)Kormendi(1988:347)de Leeuw andvan derZouwen (1988)Sykes andC o llin s(1988:311)incom eincom eattitudesincom evariousalcoholm ore m issingphonemore missingphonemore DK/NAphonem ore m issingphoneslightly m ore likelyto be missing onphonem ore likely to bemissing inpersonal

Effect of mode: Comments about itemnonresponse• Differences in item nonresponse by mode appear to decline over time asorganizations get experience with telephone surveys• Some differences due to variation in question design• Item nonresponse is probably further reduced with computer-assistedmethods which are increasingly availableEffect of mode: MeasurementAnswers to survey questions - Parallel open questionsStudy Topic FTF vs telephoneGroves(1978:260)Jordan et al.(1980:217-218)*Sykes andCollins(1988:307,314)Problems facingthe countryreasons for notseeing an MDN acuteconditionsN chronicconditionsN currentprescriptionsattitudesexplanationsMore mentions inpersonalno differenceno differenceno differenceno differencemore mentions inpersonalmore mentions ontelephoneEffect of mode may be greater for open questions aboutattitude objectsEffect of mode: MeasurementAnswers to survey questions - Cards andchecklists (Jordan et al. 1980:218)Effect of mode: MeasurementAnswers to survey questions - Response patterns(Groves 1979:200-201)Number of ItemsMentionedPhone PersonalVoluntary preventive health 1.4 1.0behaviorKinds of family advice 1.3 .9Kinds of advice from friends 1.1 .61Personal uses card, telephone uses checklistAll differences significantPercent choosing same answer Phone Personal3 or more times over 5 itemsDelighted-terrible (unfolded) 59 53Dissatisfied-satisfied(numeric partially-labeled)58 55Percent choosing specificcategories 3 or more timesover 5 itemsPhonePersonalDelighted-terribleMixed 8 2Mostly satisfied 14 13Pleased 18 23Delighted 20 14There may be aslightly greatertendency to usethe samecategoryrepeatedly inphone vs face-toface

Effect of mode: MeasurementAnswers to survey questions - Responsepatterns (Jordan et al. 1980:218)Mean Scores on ResponsePattern CountsPhone PersonalAgreement 13.9 12.5Evasiveness .6 .5Extremeness 2.5 1.9Effect of mode: MeasurementAnswers to survey questions - Social desirability• Lower visibility on telephone may lower pressure for desirable answers• Less intimacy, desire to conform• Fewer characteristics of interviewer can be seen as relevant• Lower visibility on telephone may increase perception of possible threat• Interviewer cannot display credentials• Status of interview as interview may remain ambiguousCompared to telephone interviews, answers to rating scaleswith "vague quantifiers" in self-administered instrumentsappear to be (review in Dillman and Tarnai 1988):less extremeshow fewer category order effectsEffect of mode: MeasurementAnswers to survey questions - Social desirabilityof face-to-face vs phoneTheory of mode effects for in-person data collection(Tourangeau and Smith 1998)Hochstim (1967)Locander et al.(1976)Sykes and Collins(1988:306)Sykes and Collins(1988: 312)de Leeuw and vander Zouwen (1988)apparent ranking:personal,telephone, mailsimilar to eachotherpattern of more SDin personal ingeneral surveymore SD inpersonal for Qsabout alcoholSD lower inpersonal

Mode Effects and Reports of Illicit Drug Use: Proportions of RespondentsReporting Drug Use Relative to SAQ (Tourangeau and Smith 1998, Table 22.1)Mode Effects and Reports of Illicit Drug Use: Proportions ofRespondents Reporting Drug Use Relative to SAQ (Tourangeau andSmith 1998, Table 22.1)Time FrameStudy Year Mode vs Mode Drug PastMonthPastYearLifetimeAquilino (1994) In-person SAQ Cocaine 0.67 0.75 0.88Marijuana 0.83 .0.77 0.98Telephone SAQ Cocaine 1.00 1.00 0.76Marijuana 0.67 0.62 0.96AquilinoandLoSciutoGfroererandHughesSchober etal.Turner,Lessler,andDevore(1990) Telephone SAQ – Cocaine 0.83 0.85 1.10WhitesMarijuana 1.00 0.96 1.00Telephone SAQ – Cocaine 0.60 0.82 0.82BlacksMarijuana 0.41 0.72 0.80(1992) Telephone SAQ Cocaine 0.49 0.70Marijuana 0.65 0.75(1992) In-person SAQ Cocaine 0.60 0.75 0.89Marijuana 0.75 0.83 0.99(1992) In-person SAQ Cocaine 0.42 0.68 0.94Marijuana 0.62 0.77 0.95• In Aquilino’s study, ratioof proportion of Rsreporting cocaine use byphone to proportion of Rsreporting by SAQ is .67• Ratios under 1 indicatelower reporting in modeother than SAQ• No ratio is greater than 1• Ratios tend to besmallest for most recenttime frame and closer to1 for lifetimeMean number of adult lifetime sex partners reported bymen and women, 1989 GSS (Smith 1992, Table 7)Males Females Males:FemalesUnadjusted 13.00 3.24 4.06:1Adjusted for 12.05 3.03 3.98:1nonresponseAdjusted forextreme values9.36 3.02 3.10:1• In a closed population, reports of men and women should yield the sameestimates of number of sexual partners.• Estimates based on men's reports are higher than estimates based onwomen's reports.• Results suggest that techniques that decrease men's reports or increasewomen's reports improve reporting.Mean reported sex partners by mode of interview (ACASIExperiment, Tourangeau and Smith 1996, Table 3)ModePastYearPast 5YearsLifetimeACASI 2.26 4.52 7.05CASI 1.87 2.99 5.75CAPI 2.14 3.44 5.51• Effect of mode is significant for lifetime reports and marginally significantfor 5-year reports.• ACASI yields higher reports than CASI for lifetime and 5-year reports.• Cell sizes range from 86 to 104. Significance tests based on logged data.Typology of Web SurveysWeb surveys withgeneral invitationsNo0. Entertainment polls1. Unrestricted self-selectedsurveysNon-probability surveysProbability-based surveysNo2: Volunteer opt-in panels?: Surveys of spam listsList of participants invitedto the survey?Yes, prior to datacollectionWeb surveys withindividual invitationsProbability sample?YesYes, generated duringdata collectionIntercept surveys3. Pop-up surveys3. Selective banner ads4: List-based samples5: Web option in mixed-mode surveys6: Pre-recruited lists of Internet users7: Pre-recruited panels of full populationSource: based on Lozar Manfreda’s (2001) revision of Couper (2001)48

Web-based surveys: Considerations• Security• Server capacity• Additional layer of testing related to usability• Variable platform environment• Questionnaire design• Usability• Graphics, video streamOther modes: Diary surveys• Major uses: expenditures, time use, nutrition• Advantages• Avoid recall errors• Obtain detailed information• Reduce proxy reporting, social desirability effects• Reduce costs, relative to face to face interview• Disadvantages:• Declining interest, reporting over time• Underreporting• Change of behavior• Structure and complexity of diary• Problems of late placement and recall periodOther modes: Administrative recordsOther modes: Direct observation• Major uses: income data (tax forms), hospital data• Advantages:• Relatively cheap (data already exist)• Low (no) additional respondent burden• May augment survey data• May provide opportunities for validity studies• Disadvantages:• Limited to data available on records• Quality and timeliness of information on records• Coverage problems• Informed consent, confidentiality issues• Examples of measurements by visual inspection• Condition of housing unit or neighborhood• Display of books, furniture in home• Interaction among household members• Physical condition of respondent• Can be unobtrusive or obtrusive• Generally requires more careful interviewer training because of lack ofstructure of visual observation• Little is known about interviewer variability for such measures

Summary: Advantages of face-to-face surveys• Face-to-face interviews are only possible if the address of the sample unit isavailable• Most compatible with area probability and list samples• Nonparticipation• Can contact respondents without telephones• Best for gaining cooperation (high response rate)• Physical presence of interviewer provides more information aboutinterviewer, which can aid in building trust• Physical presence provides interviewer more information about respondent,which can aid her in tailoring appeals for cooperation• Measurement• Advantages of interviewer administration• answer questions and provide clarification• probe• following skips• longer, more complex interviews possible• use of visual aids• Advantages of interviewer presence• Permits addition of self-administered portion• Permits other types of data collection (observation, visual cues)Summary: Disadvantages of face-to-face surveys• Staff and field costs• Need trained staff of geographically dispersed interviewers• Training and supervision more complicated• Workload must be maintained to retain staff• Requires longer field period to collect data than telephone method• These may need to higher cost than telephone• Nonparticipation• Some areas (high rise buildings, high crime areas) may be lessaccessible to personal interview• Measurement• Effect of interviewer• Interviewer bias (cheating, distortion, errors)• Physical presence provides respondent more information aboutinterviewer, which may increase impact of social presence orrapport on socially desirable answersSummary: Advantages of telephone surveys• Telephone interviews are only possible if the telephone number is available• Most compatible with RDD or list samples• Sampling error• Can reach geographically dispersed sample• List samples can be spread over a wide area• RDD samples have low clustering• Staff and field costs• No travel costs• Staff can be centralized, reducing costs of recruiting, training, supervising, and retaining• Field period may be shorter than FTF or mail• Leads to lower costs than FTF• Nonparticipation• Some units may be easier or safer to reach by telephone than personal visit• Restricted access or high crime areas are easier to reach by telephone• Measurement• Advantages of interviewer administration• answer questions and provide clarification• probe• following skips• longer, more complex interviews possible than self-administered on paper• Better interviewer training and supervision in centralized facility• Interviewer variance and bias reducedSummary: Disadvantages of telephone surveys• Frame: Coverage and eligibility• Those without phone or with only cell phone cannot be included• For RDD designs, this results in coverage problems• More difficult to identify ineligible, non-household numbers• Nonparticipation• For list designs, units without telephones cannot be contacted andbecome unit nonrespondents• Access problems (answering machines, caller-ID)• More limited methods of recruitment (e.g., may not always haveaddress)• Nonresponse typically higher than FTF• Measurement• Questionnaire constraints• Fewer response alternatives• No visual aids• No interviewer observations

Summary: Advantages of mail surveysSummary: Disadvantages of mail surveys• Mail surveys require an address• Most compatible with list samples with a named respondent• Staff and field costs• Relatively low cost• Minimal staff and facilities required• Sample• Provides access to widely dispersed sample• Design does not need to be clustered• Measurement• Respondents have time to give thoughtful answers, look up records, orconsult with others• Best for sensitive questions, avoidance of social desirability bias• Reduced response or question order effects• Frame• Need for good mailing address limits designs with which it can be used• Within-household selection of respondents difficult, so respondent mustusually be identified on frame• Nonparticipation• Relatively low response rates• Measurement• Disadvantages associated with lack of interviewer presence• Literacy requirement limits utility• Short, less complex questionnaires• Increased item missing data