quantitative research methods

quantitative research

research focused on the collection and analysis of numerical data to describe, explain, predict, or control variables and phenomena of interest

additional characteristics

• literature review is more central to research design than in qualitative research

• research purposes/goals are typically specific and narrow

• data collection procedures are specified prior to beginning of study

• sampling strategies — focus on random selection in order to improve generalizability — collect data from a large number of individuals

• data analysis and interpretation of results are entirely statistical in nature

• reporting of results is very standardized and almost “pre-formatted”

research process

1. identification of the research problem to be studied

2. statement of one, or several, pertinent research questions and/or hypotheses

3. review of related literature: can inform decisions regarding research design, sampling etc.

4. development of a written lit review

5. development of a research plan

6. collection of data

7. analysis of data

8. development of conclusions and recommendations

9. preparation of a final research report

non-experimental research designs

no manipulation to variables — descriptive research

descriptive research

• goal to describe and make interpretations about individuals, setting and so on

• includes observational research and survey research

observational research

• focus on quantification of observations in order to measure complexities of human behavior

• yields data that depicts complexity of human behaviour

survey research

• describe characteristics of group or population

• representative respondents selected from population

descriptive research — data collection

1. direct administration: access to all, or most, members of a group in one place

2. mail surveys: sending a hard copy to each individual

3. telephone surveys: administered individually and may be expensive

4. interviews: most costly because most done individually and face-to-face

5. electronic surveys: e-mail, web-based

types of surveys

• descriptive surveys

• cross-sectional survey (census)

• longitudinal survey

descriptive surveys

one-shot survey to describe characteristics of a sample at one point in time

cross-sectional survey (census)

examination of characteristics of (and differences among) many samples or populations measured at one point in time

longitudinal survey

• group or cohort studied at different points in time

  • trend survey: changes within specifically identified population over time

  • cohort study: specified population within a subgroup

  • panel study: same people examined over specific length of time

descriptive research — strengths and limitations

• efficient data collection for large number of people

• allows for greater degree of generalizability

• options allow for customization of survey research process

• potentially low response rates

• requirements of some modes of survey delivery

• surveys result in self-report data

correlation research

measure of relationships between two or more variables

explanatory correlation studies vs predictive correlational studies

• explanatory correlation studies: goal to comprehend and describe certain related events, conditions and behaviors

• predictive correlational studies: predict future conditions or behaviors in one variable from what we know of another variable

correlational research strengths/limitations

• strengths

  • simplicity of design

  • often appropriate for novice researchers

• limitations

  • correlation ≠ causation

  • must ensure validity and reliability of data

  • resulting correlation coefficient will look meaningful but can actually be misleading

causal-comparative research

to determine why or how two existing groups are different from one another

causal-comparative research process

1. identification of topic/problem

2. review of related literature

3. identification and selection of participants

4. specify the design and procedures for data collection

5. collection of data

6. analysis of data

7. answering research questions and drawing conclusions

causal-comparative research — strengths and limitations

• solid alternative when experimental designs are not feasible or possible

• may not be possible to manipulate the grouping variable

• cause had already occurred; no control over it

experimental research design

researcher establishes different treatments or conditions and studies thier effects on participants — categories

categories

per-experimental research designs, quasi-experimental research designs, true experimental research designs and single-subject research designs

random selection vs random assignment

• random selection: process of choosing, in random fashion, individuals for participation, in order for each member to have equal chance of selection

• random assignment: each individual randomly selected to participate has equal chance of being assigned to any group compared in the studies

pre-experimental research

• does not do a good job at controlling for extraneous variables

• appropriate for preliminary investigations of research topics

• includes one-shot case study, one-group pretest-posttest design, and static-group comparison design

pre-experimental research — strengths and limitations

• good for preliminary investigations

• weak design

• no control over extraneous variables

• very difficult to draw definitive conclusions

quasi-experimental designs

• closest to true experimental designs

• no random assignment of participants to group

• appropriate for designs requiring the use of participants in existing groups

quasi-experimental designs — strengths and limitations

• good option when random assignment is not feasible

• vast improvement over pre-experimental designs

• still don’t control extraneous variables

• still difficult to draw definitive conclusions

true experimental research

• involves both random selection and random assignment

• all designs have at least one comparison group

• simplest design: posttest-only control group design

• others: pretest-posttest control group design and solomon four-group design

true experimental research — strengths and limitations

• capacity to draw strong conclusions about cause-and-effect relationships

• requirements are extremely stringent (sometimes prohibitive)

• must take care to counteract threats of validity

single-subject experimental research design

• experimental-type studies conducted on individual participants

• focus on promoting a change in behavior

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single-subject experimental research design — strengths and limitations

• ability to focus on an individual

• ability to study effectiveness of a treatment on only that participant

• alternative explanations will always exist

• must find ways to factor out these alternatives