Upload
azura-zaki
View
7.863
Download
0
Tags:
Embed Size (px)
Citation preview
EDU702 Research Methodology
Quantitative Research
Prepared byAzurawati Binti Wok Zaki
2011313879ED7701A2
Chapter 16:Causal-Comparative
Research
(Ex post facto ResearchNon-experimental research)
THE AIM
to determine the cause of existing differences among groups.
Causal-Comparative Research is Differentiated from Experimental
Research
• In an experiment, the independent variable is manipulated by the researcher.
• In causal comparative research the independent has already occurred.– Examples of independent variables
include socioeconomic status, pre-school history, number of siblings, and so on.
Three types of causal-comparative research
Causal- comparative and Correlational Research
• Similarities: researchers explore relationship
among variablesseek identify variables that are
worthy of later exploration through experimental research.
provide guidance for subsequent experimental studies.
attempt to explore causation
Differences:Causal-Comparative vs Correlational
- Compare 2 or more groups of subjects
- Require a score on each variable for each subject.
-Involve at least one categorical variables (group membership)
- Investigate 2 (or more) quantitative variables
- Often compare averages or use crossbreak tables.
- Analyse data using scatterplots
Causal-comparative and Experimental Research
• Similarities:• - Require at least one
categorical variable (group membership).
• - Compare group performances (average score) to determine relationship.
• - Both typically compare separate group of subjects.
Differences: Causal-Comparative vs Experimental
- No manipulation takes place
- Independent variable is manipulated
- Provide much weaker evidence for causation than do experimental studies.
- The group are already formed (the researcher must locate them)
- The researcher can assign subjects to treatment groups
- The researcher has much greater flexibility in formulating the structure of the design.
Value of Causal Comparative Research
• Uncovers relationships to be investigated experimentally.
• Used to establish cause-effect when experimental design not possible.
• Less expensive and time consuming than experimental research.
• Note: if you conduct a quantitative research study it most likely will be a causal-comparative study.
• More Examples:• How does preschool attendance
affect social maturity at the end of the first grade?
• How does having a working mother affect a child’s school absenteeism?
STEPS TAKEN
1) Problem Formulation2) Sample
3) Instrumentation4) Design
Threats
• Subject Characteristics• - Matching the subjects• - Finding or Creating
Homogeneous Subgroups• - Statistical Matching
Data Analysis in Causal-Comparative Studies
• To construct frequency polygon• Means and standard deviations are
usually calculated in the variables involved are quantitative.
• The most used test is a t-test for differences between means.
• Analysis of covariance is useful.• The results should always be
interpreted with caution.
Chapter 17:Survey Research
The most popular technique for
gathering primary data in which a
researcher interacts with people to
obtain facts, opinions,
and attitudes.
The Purpose of Survey Research
Types of Surveysi) Cross-sectional study
• A study in which various segments of a population are sampled. E.g. managers and non-managers.
• Data are collected at a single moment in time.
• When an entire population is surveyed: Census
example
• A professor of Mathematics might collect data from a sample of all the high school mathematics teachers in a particular state about their interests in earning a master’s degree in Mathematics from his university.
ii) Longitudinal study
• Longitudinal survey• - information is collected at
different points in time in order to study changes over time.
3 Longitudinal designs
Trend study
Cohort Study
Panel Study
different samples from a population whose member may change are surveyed at different points in time.
a particular population whose members do not change over the course of the survey.
the researcher surveys the same sample of individuals at different times during the course of the survey.
Examples:
• Trend study:- A researcher might be interested in the
attitudes of high school principals towards the use of flexible scheduling. He would select a sample each year from a current listing of high school principals throughout the year. The same individual would not be the sampled each year, he would compare responses from year to year to see whether any trends were apparent.
Cohort study
• A researcher would like to study growth in teaching effectiveness of all the 1st year teachers who had graduated in the past 5 years from a university. The names of all would be listed, and different sample would be selected from this listing at different times.
Panel study
• A researcher select a sample of last year’s graduates from a university who are 1st year teachers and survey on the same individual several times during the teaching years.
Steps taken
Defining the problem
- It should be interesting and
important to motivate individuals to
respond.
Identifying the target population
Forms of Survey Research
Mail SurveysMail Surveys
Telephone surveysTelephone surveysPersonal InterviewsPersonal Interviews
Internet surveysInternet surveys
Comparison of three kinds of surveysComparison of three kinds of surveysCOMPARISON OF SURVEY TECHNIQUES
Advantages and Disadvantages Direct Administration
Tele-phone
Mail Inter-view
Comparative Cost Lowest Inter-mediate
Inter-mediate
High
Facilities needed? Yes No No Yes
Require training of questioner?
Yes Yes No Yes
Data collection time Shortest Short Longer Longest
Response rate Very high Good Poorest Very High
Group administration possible
Yes No No Yes
Allow for random sampling? Possibly Yes Yes Yes
Require literate sample? Yes No No No
Permit follow-up-questions? No Yes Yes Yes
Encourage response to sensitive topics?
Somewhat Somewhat
Somewhat
Weak
Standardization of responses Easy Somewhat
Somewhat
Hardest
Questionnaire Design
Open-EndedQuestion
Open-EndedQuestion
Closed-EndedQuestion
Closed-EndedQuestion
An interview question that encourages an answer phrased in respondent’s
own words.
An interview question that encourages an answer phrased in respondent’s
own words.
An interview question that asks the respondent to make a selection
from a limited list of responses.
An interview question that asks the respondent to make a selection
from a limited list of responses.
Advantages Closed-ended Open-ended
-Enhance consistency of response across respondents
- Allow more freedom of response
-Easier and faster to tabulate - Easier to construct
- More popular with respondents - Permit follow-up by interviewer
Disadvantages- May limit breadth of response - Tend to produce responses that
are consistent in length and content across respondents
- Take more time to construct - Both questions and responses subjects to misinterpretation
- Require more questions to cover the research topic
- Harder to tabulate and synthesize
Typical problems in wording questionsTypical problems in wording questionsTYPICAL PROBLEMS IN WORDING QUESTIONS
Respondent Error
• A classification of sample bias resulting from some respondent action
Non-response -Total Nonresponse
Non-response-total nonresponse
• Not enough people respond or refuse to respond
• NONRESPONDENTS - People who refuse to cooperate
• NOT-AT-HOMES• SELF-SELECTION BIAS
especially in case of self-administered questionnaire. People respond to only those they like.
Item Nonresponse
- The respondent may not know the answer to a particular question, the respondent may find the questions embarrassing or irrelevant.
The END
Thank You