URBP 204 A Class 9

Note: the class notes summarize Salkind (2004) Chapters 12, 13 and 15

CLASS 9

• Correlation Coefficient• Tutorial 3 • Give back Rev Ex Set 1 and Neighborhood Profile Memo • Survey Research

CLASS 10

• Probability- based Sampling• Survey Research • Experiments (Time Permitting)• Qualitative Field Research (Time Permitting)• Introduce Mid-Term• Introduce Exercise Set 3• Factorial ANOVA Example• Lab-Time for Term Project

Types of probability sampling designs

Simple random samplingAll elements are numbered and then a predetermined number are randomly selected.(may get clusters, should know the entire population)

Systematic samplingEvery kth element chosenFor e.g.: every 10th house; danger of biases (every 10th house maybe a corner house - traffic noise)

Stratified SamplingReduce sampling error by less variabilitye.g. single-family houses and apartmentsWithin the strata we may employ simple random or systematic sampling

Multistage clustering samplingSampling of clusters City-wide study - list census tracts - choose sample of census tracts - listall block groups - choose sample of block groups - list all blocks -choose sample of blocks - list all h.h.s - choose sample of h.h.sMay also stratify the sample: Stratification in multistage cluster sampling

Note: the class notes summarize Babbie (2004) Chapter 7, and part of Chapter 9.

Survey Research

Guidelines for asking questions

• Open ended vs close ended questionOpen ended – more rich; coding difficult; more chances of error while recordingClose ended – less rich; responses may be straight jacketed; less chances of recordingerror; careful about exhaustiveness

• Make items clear - income last year – based on W-2?

• Avoid double-barreled questions – Should San Jose cut back on roadconstruction and increase allocation for affordable housing?

• Respondent must be competent and willing to answer

• Questions should be relevant

• Keep it short

Note: the class notes summarize Babbie (2004) Chapter 7, and part of Chapter 9.

Guidelines for asking questions contd….

• Avoid negative terms – do you think we should not do this?

• Avoid biased items and terms – do you agree with the recent health reports’ finding that……

Note: the class notes summarize Babbie (2004) Chapter 7, and part of Chapter 9.

Guidelines for survey interviewing

• Modest yet neat appearance

• Avoid voice inflections

• Be neutral

• Be polite

• Be familiar with the questions

• Don’t add your words to the question

• Record responses exactly

• Gently probe for responses/ clarifications

Note: the class notes summarize Babbie (2004) Chapter 7, and part of Chapter 9.

Questionnaire Construction

• Not cluttered• Professional look; clear instructions on how to choose responses (especially if self-administered), • Use of contingency questions• Use of matrix format• Order of questions – bias due to the order (negative aspects of sprawl; then ask is sprawl bad); in self- administered begin with interesting questions; in interviews – uncomplicated questions first• Include clear instructions and introductory statements (now think about the last one week….)• Pretest the questionnaire

Self- administered Questionnaire

Mail; home delivery or combination; questionnaire at a public gathering; etc.

If mail deliveryMonitor the returnFollow up mailings

Telephone Surveys

Unlisted number – random digit dialingAdvantages – cheap and quick; no dress code; probe more sensitive areas; more quality control possible as central location; safety.Disadvantages – compete with bogus surveys; easy to hang up; answering machines; cell phones

Comparison of self-administered and interview survey methods

Advantages of self- administered over face-to-face interviews• Cheaper• More geographically extensive • Require smaller staff• Easy to probe sensitive topics

Advantages of face-to-face interviews over self- administered questionnaires• Larger response rate• More effective for complicated issues• May also note other information - condition of the neighborhood, etc.

Strengths and weaknesses of survey research

Strengths• Describe characteristics of a large population• Make large samples feasible • More flexible – can cover several topics• Strong on reliability

Weakness• Have to ascribe the same intent to responses to questions related to complex concepts• Least common denominator – superficial in coverage of complex topics• Life situation/ context not known• Can not change questions mid-way• Respondent may form opinion at the moment• Weak on validity

MODES OF OBSERVATION

• Experiments

• Surveys

• Qualitative Field Research

• Others ( for example, content analysis)

EXPERIMENTS

Taking actionObserving consequences of the action

Suited to :a) Research “well-defined concepts and propositions” (Babbie 221)b) Explanatory studiesc) Small groups

Can be:Laboratory experiments (health sciences, physical sciences, etc.)Natural experiments (naturally occurring events)

Components of a classical experiment

a) Dependent and independent variablesb) Pretesting and posttestingc) Experimental and control groups

Effect of knowledge of good examples of high density developmenton the people’s perception about density

Selecting subjectsRandomizationMatching (Income, urban vs rural, race, etc.) - like quota samplingCombination of both, akin to stratified sampling

Variations in Experimental Design

Preexperimental research designs

• One shot case study – no pretest – just show examples of good high density developments and then measure the perception

• One- group pretest- posttest design – no control group – not sure whether examples caused the effect

• Static-group comparison – no pretest; control group present- randomization of subjects important (examples of good high density development showed to one group and not to the other)

Validity Issues in Experimental Research

Internal validity issues- does the conclusion reflect the process?

History – major event during the experimentMaturation – people old, tired, sleepy. Slept while shown examples of high density development!Testing – testing and retesting affects subjects’ responsesInstrumentation- pretest and posttest measures differentStatistical regression- extreme positions undesirable as these people are likely to improve anywaysSelection biases – groups should be comparableExperimental mortality – bias due to subjects leavingCausal time order – dependent variable causes changes in the stimulus – e.g. rat causes change in virus; Diffusion of treatments- experimental and control groups in communication Compensation – to the control group. Thus they are no longer ideal control group.Compensatory rivalry – extra efforts by the control groupDemoralization – of the control group

External Validity Issues in Experimental Research

Is the experiment generalizable?

What if instead of slides of good high density development we showed a film?

Natural experimentsNatural events as stimulus- e.g. hurricanes, bombings, etc.

Some of the Limitations:Comparable control groups difficult to findSelection of subjects not random

Strengths and Weaknesses of the ExperimentalMethod

Strengths• Replication is easy – more reliability• Interaction of dependent and independent variable easy to isolate

Weaknesses• Artificiality- changes may not occur in more natural settings

Qualitative Field Research

Topics appropriate for Field Research• Hard to quantify• Nuances • Important to observe in natural settings• Social processes over time• Study of relationships, roles, groups, subcultures, lifestyles, etc.

Special Role of Observers

Complete observer – does not participate at all. Less appreciation ofwhat is being studied.Complete participant – full participation – genuine or pretend; forsubjects not a researcher. Issue of deception; affecting the study; goingnative!Somewhere in between- participate but let the subjects know that youare a researcher

Relations to subject

Pretend to join or really join - adopt the subjects’ point of view or viewthem critically- or combination

The setting can have an impact – e.g. homeless on the streets,welfare office, or shelter

Swayed by subjects’ personal lives (problems, etc.) - threat of loosingscientific objectivity

Notion of superiority over the subjects

Strengths and Weaknesses of Qualitative FieldResearch

StrengthsNot superficialFlexibility- research design; begin the observationCan be inexpensiveGreater validity than survey and experimental design

WeaknessesCan’t statistically describe a large populationNot good at predicting futureLess reliability than the survey and experimental design