2Descriptive Research Designs Observation StudiesCorrelational ResearchDevelopmental DesignsSurvey Research
3Observation Studies Characteristics: - might involve humans, animals, plants, nonliving objects- tends to have a particular prespecified focus- behavior being studied is quantified in some way- involves considerable advance planning, meticulousattention to detail, and a great deal of time- provides a quantitative alternative to qualitativeapproaches, such as ethnographies and grounded theorystudies
4Maintaining Objectivity in Observation StudiesDefine the behavior studied precisely and concretely so that it is easilyrecognized when it occurs.Divide the observation period into small segments and record whetherthe behavior does or does not occur in each segment.Use a rating scale to evaluate the behavior in terms of specific dimensions.Have two or three people rate the same behavior independently, withoutknowledge of one another’s ratings.Train the raters to use specific criteria when counting or evaluating thebehavior; continue training until consistent ratings are obtained for anysingle occurrence of the behavior.
5Correlational Research A correlational study examines the extent to which differences in onevariable or characteristic are related to differences in one or moreother variables or characteristics.In correlational studies, researchers gather data about two or morecharacteristics for a particular group of people or other appropriateunits of study in order to determine whether and in what way thesecharacteristics might be interrelated.Correlational data is plotted on a scatter plot.Correlation does not, in and of itself, indicate causation.
6Developmental Designs Two Developmental Designs:1. Cross-sectional study: people from several different agegroups are sampled and compared.2. Longitudinal study: a single group of people is followedover time, and data related to the characteristics underinvestigation are collected at various times.
7Cross-Sectional vs Developmental Studies Cross-sectional studies are easier to conduct because all of the data canbe collected at one time. In a longitudinal study, data is collected overa period of months or years and participants may drop out.In a longitudinal design, when people respond repeatedly to the samemeasurement instrument, the characteristic being measured maychange because of their practice with the instrument.In a cross-sectional design, different age groups may represent differentlife experiences. This poses a threat to internal validity.In a cross-sectional design, correlations between characteristics atdifferent age levels can’t be computed.
8The Cohort-Sequential Developmental DesignAddresses some of the weaknesses of longitudinal and cross-sectionaldesigns.The researcher begins with two or more age groups (the cross-sectionalpiece) and follows each age group over a period of time (thelongitudinal piece).Like a longitudinal study, the cohort-sequential study allows calculationof correlations between measures taken at two different time periods;therefore, predictions can be made across time.
9Survey ResearchInvolves acquiring information about one or more groups of people —about their characteristics, opinions, attitudes, etc. – by asking themquestions and tabulating the answers.Goal is to learn about a large population by surveying a sample of thatpopulation.Also called a descriptive survey or normative survey.Simple design – the researcher poses a series of questions, quantifiesthe responses, and draws inferences about a particular populationfrom the responses of the sample.Captures a fleeting moment of time; by drawing conclusions from thetransitory collection of data, extrapolation can be made about stateof affairs over a longer period of time.Relies on self-report data.
10Types of Survey Research face-to-face interviewtelephone interviewwritten questionnairethe Internet
11The Face-to-Face Interview StructuredEnables the researcher to establish rapport with participantsYields the highest response rates in survey researchTime and expense involved may be prohibitive
12Telephone Interviews Structured Less expensive and time-consuming than face-to-faceinterviewsAccessible participantsResponse rate lower than for face-to-face interviews buthigher than for mailed questionnaires
13Paper-and-Pencil Questionnaires Can be sent out to large groups of people over a largegeographical areaParticipants can respond to questions with assurance ofremaining anonymous and thus may be more truthfulthan in face-to-face or telephone interviewsHave a low return rateOften make use of checklists and rating scales
14Using Checklists and Rating Scales Checklist: a list of behaviors, characteristics,or other entities under investigation.Rating Scale: used when a behavior, attitude, orother phenomenon of interest needs to beevaluated on a continuum (“never” to “always”)- Likert Scale
15Conducting Interviews in a Quantitative Study Guidelines:Conducting Interviews in a Quantitative StudyIdentify questions in advance.Consider how participants’ cultural backgrounds may influence responses.Make sure interviewees are representative of the group.Find a suitable location.Get written permission.Establish and maintain rapport.Focus on the actual rather than on the abstract/hypothetical.8. Don’t put words in people’s mouths.9. Record responses verbatim.
16Conducting Interviews in a Quantitative Study (con’t) Guidelines:Conducting Interviews in a Quantitative Study (con’t)10. Keep your reactions to yourself.11. Remember you’re not necessarily getting the facts.12. As you write questions, think about how to quantify responses.13. Consider asking questions that will elicit qualitative information.14. Pilot-test the questions.15. Restrict each question to a single idea.16. Save controversial questions for the latter part of the interview.17. Seek clarifying information when necessary.
17Guidelines: Constructing a Questionnaire Keep it short.Keep the respondent’s task simple.Provide clear instructions.Use simple, clear, unambiguous language.Give a rationale for any item for which the purpose is unclear.Check for unwarranted assumptions implicit in the question.
18Guidelines: Constructing a Questionnaire (con’t) 7. Word questions in ways that don’t give clues about preferred ormore desirable responses.Determine in advance how you will code the responses.Check for consistency.Conduct one or more pilot tests to determine the validity of yourquestionnaire.Scrutinize the almost-final product one more time to make sure itaddresses your needs.12. Make the questionnaire attractive and professional looking.
19Guidelines: Maximizing the Return Rate for a Mailed Questionnaire Consider the timing.Make a good first impression.Motivate potential respondents.Include a self-addressed, stamped envelope.Offer the results of your study.Be gently persistent.
20Practical Application: Computerizing Data Collection in Descriptive ResearchDirectly enter data as an observation is made.Use the computer as a tape recorder.Look for peripheral devices that can aid data collection.Administer a questionnaire on a computer.Use the computer to monitor the quality of the data being collected.
21Sampling Designs in a Descriptive Study Probability Sampling: the researcher specifies inadvance that each segment of the population isrepresented in the sample.Nonprobability Sampling: the researcher has noway of forecasting or guaranteeing that eachelement of the population will be representedin the sample. Some members of the populationhave little or no chance of being sampled.
22Probability Sampling way that each member of the population has an Random selection: choosing a sample in such away that each member of the population has anequal chance of being selected; assumes that thecharacteristics of the sample approximate thecharacteristics of the total population.
23Probability Sampling Techniques ▪ simple random sampling: least sophisticated of all samplingdesigns; sample is chosen by simple random selection.▪ stratified random sampling: the researcher samples equally fromeach one of the layers in an overall population.▪ proportional stratified sampling: the researcher samples proportionallyfrom each one of the layers in an overall population.▪ cluster sampling: occurs when the population of interest is spread outover a large area; the large area is subdivided into smaller units;a subset of identified clusters is randomly selected.▪ systematic sampling: involves selecting individuals according to apredetermined sequence, which must originate by chance.
24Nonprobability Sampling Techniques Convenience sampling: also known as accidental sampling;takes samples that are readily available; appropriate forless demanding research problems.Quota sampling: a variation of convenience sampling;selects participants in the same proportion that they arefound in the general population, but not in a randomfashion.Purposive sampling: participants are chosen for a particularpurpose; the researcher must always provide a rationaleexplaining the selection of a particular sample.
25Choosing an Appropriate Sample Size The larger the sample, the better.For smaller populations (N=100 or fewer), survey the entirepopulation.If population is around 500, sample 50%.If population is around 1,500, sample 20%.If population is over 5,000, a sample size of 400 is fine.The larger the population, the smaller the percentageneeded for a representative sample.
26Sampling BiasBias: any influence, condition, or set of conditions thatsingly or in combination distort the data.Sampling Bias: any influence that may disturb therandomness by which the choice of a sample populationhas been selected.Strategies for identifying sampling bias:- Scrutinize the questionnaire for items that may be influenced by factors thatdistinguish respondents from nonrespondents.- Compare responses that were returned quickly with those that were returnedlater (may reflect the kinds of responses that nonrespondents would have given.- Randomly select a small number of nonrespondents and match their answersagainst those of respondents.
27Some Final Suggestions Questions related to your research project:▪ Why is a description of this population and/or phenomenon valuable?▪ What specific data will I need to solve the research problem and subproblems?▪ What procedures do I need to get the information? How should I implement theprocedures?▪ How do I get a sample that is truly reflective of the entire population about whichI am concerned?▪ How can I collect my data in a way that ensures no misrepresentations ormisunderstandings?▪ How do I control for possible bias in the collection and description of data?▪ What do I do with the data once I have collected them? How do I organize themand prepare them for analysis?