Quasi experiemtal Quasi experiemtal designs and field designs and field

researchresearch

Variations in classical Variations in classical experimentsexperiments

Post test only designsPost test only designsUsed when pretesting might affect Used when pretesting might affect

the resultsthe resultsTo assess this could use a 4 group To assess this could use a 4 group

design, experimental pre-postdesign, experimental pre-postExperimental postExperimental postControl pre-postControl pre-postControl postControl post

Non-equivalent groupsNon-equivalent groups

Comparison group rather than control Comparison group rather than control group (difference is random group (difference is random assignment)assignment)

Use of matchingUse of matchingWidom’s study of child abuse and Widom’s study of child abuse and

criminalitycriminalityAbused matched with a non-abused Abused matched with a non-abused

group on gender, race, age, and SESgroup on gender, race, age, and SESProblem with matchingProblem with matching

Non-equivalentNon-equivalent

Predicting parole riskPredicting parole riskUse of LSIUse of LSI3 jails, one (comparison) not 3 jails, one (comparison) not

informed of LSI scoresinformed of LSI scores In all groups, LSI predictive of further In all groups, LSI predictive of further

recidivismrecidivism Jails who knew LSI scores released Jails who knew LSI scores released

more low risk offendersmore low risk offenders

Non-equivalentNon-equivalent

Telephone service areas with caller Telephone service areas with caller ID compared to those without ID compared to those without services to observe effects on services to observe effects on obscene phone callsobscene phone calls

Would be deceptive if there are Would be deceptive if there are differences in obscene phone calls differences in obscene phone calls from area to area—probably not the from area to area—probably not the casecase

Less complaints in caller ID areasLess complaints in caller ID areas

CohortsCohorts

Using a particular group that all Using a particular group that all begin at the same time, compare to begin at the same time, compare to a group that began at another time. a group that began at another time. Make assumption of equivalenceMake assumption of equivalence

i.e., compare graduate students who i.e., compare graduate students who started in 2003 with those who started in 2003 with those who started in 2004started in 2004

Police class, those sentenced to Police class, those sentenced to probation in a particular month, etc.probation in a particular month, etc.

Time series designsTime series designs

Interrupted time series designInterrupted time series designTake baseline data, make an Take baseline data, make an

intervention, collect dataintervention, collect dataSee p. 196See p. 196First example, general trend, not First example, general trend, not

clear that the intervention made a clear that the intervention made a differencedifference

Current downward trend in crimeCurrent downward trend in crime

Time seriesTime series

Second pattern: random fluctuationSecond pattern: random fluctuation33rdrd pattern: immediate effect (in this pattern: immediate effect (in this

example, incapacitation)example, incapacitation)44thth pattern: more gradual effect pattern: more gradual effect

(deterrence?)(deterrence?) Interrupted time series with Interrupted time series with

nonequivalent comparison groupnonequivalent comparison group

Time seriesTime series

Time series design with switching Time series design with switching replicationsreplications

If similar changes occur in DV in If similar changes occur in DV in different places at different times, different places at different times, corresponding to when the corresponding to when the intervention was introduced, it intervention was introduced, it makes it likely that the IV did affect makes it likely that the IV did affect the DVthe DV

Field researchField research

Best for topics that can best be Best for topics that can best be understood in their natural settingunderstood in their natural setting

Example: nonverbal behaviorsExample: nonverbal behaviorsRelationship between environmental Relationship between environmental

design and crime requires design and crime requires observation of the environmentobservation of the environment

Pedestrians before and after street Pedestrians before and after street lighting was enhancedlighting was enhanced

Types of participationTypes of participation

Full participant (deception, may affect Full participant (deception, may affect what is going on, safety issues, what is going on, safety issues, incompatibility)incompatibility)

Observing around the periphery of Observing around the periphery of criminal activitycriminal activity

Observer-as-participant: identifies self Observer-as-participant: identifies self as research, interacts with subjectsas research, interacts with subjects

Police patrol studies (ride along)Police patrol studies (ride along)

Types of participationTypes of participation

Going native problemGoing native problemComplete observer, not part of the Complete observer, not part of the

action in any way. May be action in any way. May be unobtrusive, or might identify oneself unobtrusive, or might identify oneself as a research, but no interactionas a research, but no interaction

Less able to ask questionsLess able to ask questions

ObservationObservation

Observe, sometimes ask questionsObserve, sometimes ask questionsQuestions are often more Questions are often more

spontaneous, unstructured “informal spontaneous, unstructured “informal conversational interview”conversational interview”

Listening and probesListening and probes

Gaining accessGaining access

Formal organizationsFormal organizationsSponsor, letter, phone call, meetingSponsor, letter, phone call, meetingGaining access to subculturesGaining access to subculturesSponsor/informantSponsor/informantMay be people working with criminals, May be people working with criminals,

such as caseworkers, police, such as caseworkers, police, probation, lawyers, private probation, lawyers, private investigators, treatment centers, ex-investigators, treatment centers, ex-offenders, hangoutsoffenders, hangouts

Selecting subjectsSelecting subjects

Snowball samplingSnowball samplingPotential biases, i.e., only people who Potential biases, i.e., only people who

have been caught or treatedhave been caught or treatedPurposive sampling, sampling Purposive sampling, sampling

dimensionsdimensionsGroup, location, time, weatherGroup, location, time, weather

Recording observationsRecording observations

Cameras to take photosCameras to take photosVideo recordingsVideo recordingsTape recordersTape recordersField notes—what we know, what we Field notes—what we know, what we

think happenedthink happenedSketchy notes, expand later, write Sketchy notes, expand later, write

out everythingout everythingUnstructured observationUnstructured observation

Recording observationsRecording observations

Structured observationsStructured observations Instruments to guide observationsInstruments to guide observationsEnvironmental surveys (BJA), may be Environmental surveys (BJA), may be

used to plan strategiesused to plan strategiesOther observationsOther observationsPossibilities listed, recorded with Possibilities listed, recorded with

details as they happendetails as they happen

Combining with other dataCombining with other data

Linking research methodsLinking research methods i.e., combining observational studies i.e., combining observational studies

of neighborhoods with surveys of of neighborhoods with surveys of resident perceptions and crime resident perceptions and crime statisticsstatistics

Examples of studiesExamples of studies

ShopliftersShopliftersHow much? How much is identified?How much? How much is identified?Participant observation—participants Participant observation—participants

pretended to be shopperspretended to be shoppers# shoppers who stole divided total # # shoppers who stole divided total #

of shoppersof shoppersSampled days and timesSampled days and times

ShopliftersShoplifters

Everyone who entered the store was Everyone who entered the store was countedcounted

Systematic random sampling used to Systematic random sampling used to select subjectsselect subjects

Subjects followed and observedSubjects followed and observed# thefts divided by the total # thefts divided by the total

observedobserved

shopliftersshoplifters

To determine detection rates, To determine detection rates, research staff were used as research staff were used as confederate shoplifters and some of confederate shoplifters and some of them were observed by research them were observed by research staff assigned to make observations staff assigned to make observations (double blind)(double blind)

Reliability of observers could thus be Reliability of observers could thus be assessedassessed

Reliability could then be used to Reliability could then be used to adjust shoplifting ratesadjust shoplifting rates

Other studiesOther studies

Seat belts—how many people where Seat belts—how many people where seat belts?seat belts?

Sampled time of day, type of road Sampled time of day, type of road and observation site, density of auto and observation site, density of auto ownershipownership

Explicit instructions p. 307Explicit instructions p. 307

Racial profilingRacial profiling

Problem with comparing race of Problem with comparing race of drivers stopped with race of drivers stopped with race of distribution for a resident population distribution for a resident population (i.e., more non-residents may be (i.e., more non-residents may be stopped)stopped)

Estimate of drivers by observing race Estimate of drivers by observing race from toll boothsfrom toll booths

Estimate of # of cars eligible to be Estimate of # of cars eligible to be stopped stopped

ProfilingProfiling

Having observers drive 5 miles over Having observers drive 5 miles over speed limit, count the number speed limit, count the number speeding and their racespeeding and their race

Lambeth’s study—blacks 13.5% of Lambeth’s study—blacks 13.5% of drivers, 15% of those speeding. 35% drivers, 15% of those speeding. 35% stopped were black and 73% of those stopped were black and 73% of those arrested after the stop were black.arrested after the stop were black.

However, speeding not the only However, speeding not the only violationviolation

ProfilingProfiling

Lange study—examined only cases going Lange study—examined only cases going 15 or more miles over the speed limit15 or more miles over the speed limit

Bars and violence: illustrates flexibility of Bars and violence: illustrates flexibility of the method, changed study from one the method, changed study from one examining why bars were violent (even examining why bars were violent (even at violent bars, a low frequency behavior) at violent bars, a low frequency behavior) to what situations led to violenceto what situations led to violence

BarsBars

Young working class, two groups in Young working class, two groups in an encounter where they are an encounter where they are strangersstrangers

Crowded, no entertainmentCrowded, no entertainmentHigh level of drunkenness (cheap High level of drunkenness (cheap

drinks)drinks)Over aggressive bouncersOver aggressive bouncers