Quantitative Research Design Backdrop to Experimental Design Quantitative
Quantitative Research Design Backdrop to Experimental Design
Quantitative Research Process n n n n Research Objectives Background of the Problem Research Questions Hypotheses Method Data Analysis Discussions and Implications Limitations
Research Proposal A written statement of the research design n Including the purpose of the study, definition of the problem, research methodology and details of the procedures n
Sampling n n n Choosing dishes from a buffet How sampling works (photographic example) Sampling terminology ¨ Sample ¨ Target population ¨ Population element ¨ Census n Why sample? ¨ Pragmatic reasons ¨ Accurate and reliable results
Populations and Samples n Population ¨A n group of people that we wish to learn about Sample ¨ Group selected from the population that participates in the study
Statistics n Inferential statistics examine likelihood of differences found in sample to also be seen in population ¨ Groups from same population and differences due to chance or ¨ Groups from different populations
Probability versus Nonprobability Sampling n Probability sampling ¨ ¨ ¨ n Simple random sampling (Each member of population has an equal chance of being selected) Systematic sampling Stratified sampling (Random sample drawn from subgroups) Proportional versus disproportional strata Cluster sampling (Sample larger groups, followed by smaller groupings) Multistage area sampling Nonprobability sampling Convenience sampling ¨ Judgment sampling (purposive sampling) ¨ Quota sampling ¨ Snowball sampling ¨
Sample Size n Confidence level
Variables Categorical (classificatory) variable n Continuous variable n Dummy variable n Independent variable n Dependent variable n
Tips for Questionnaire Design n Two basic criteria ¨ Relevance ¨ Accuracy n n Opened-ended v. s. fixed-alternative questions Types of fixed-alternative questions (mutually exclusive) ¨ Dichotomous-alternative question ¨ Determinant-choice question ¨ Frequency-determination question ¨ Checklist question
Basic Question Formats
OPEN-ENDED QUESTIONS: Questions to which respondents give their responses freely, according to their own will.
Advantages and disadvantages of Open-ended Questions · · · n Advantages Since they do not restrict the respondent’s response, the widest scope of response can be attained. Most appropriate where the range of possible responses is broad, or cannot be predetermined. Less subject to interviewer bias. Responses may often be used as direct quotes to bring realism and life to the written report. Disadvantages · · Inappropriate for self-administered questionnaire since people tend to write more briefly than they speak. The interviewer may only record a summary of the responses given by an interview and fail to capture the interviewer’s own ideas. It is difficult to categorize and summarize the diverse responses of different respondents. May annoy a respondent and prompt him/her to terminate the interview, or ignore the mail questionnaire.
CLOSED-ENDED QUESTIONS: Questions to which respondents are required to answer from set of alternative responses provided by the researcher. Could be dichotomous or multiple choice.
Advantages and Disadvantages of Closed-ended Questions ADVANTAGES · · · All respondents reply on a standard response set. This ensures comparability of responses, facilitates coding, tabulating and interpreting the data. Easier to administer and most suited for selfadministered questionnaire. If used in interviews, less skilled interviewer may be engaged to do the job. DISADVANTAGES · · · Preparing the list of responses is timeconsuming. If the list of responses is long, the respondents may be confused. If the list of responses is not comprehensive, responses may often fail to represent the respondent’s point of views.
Considerations in choosing a question format • Nature of the property being measured – Subjective Vs objective • Previous research studies – Need for comparison with past studies • Data Collection Mode – Telephone/face-to-face-interview/mail • Scale level desired – Statistical analysis • Ability of the respondents
Phrasing and Sequencing of Questions n n n PHRASING Focus on a single issue or topic Ask precise questions using respondent’s core vocabulary Avoid ¨ ¨ ¨ use of vague words asking leading or loaded questions estimation questions double barreled questions presumptuous questions n n SEQUENCING Start with simple opening questions Place broad-based questions first; ¨ more specific and narrow questions and difficult, sensitive, embarrassing questions should come later(Funnel approach) ¨ Classification questions last. ¨ n Transition from one topic to another should be smooth
Questionnaire Layout • • Provide sufficient spaces Use prominent print for instructions Use filtered questions Do not slit the same question over two pages • Number the questions • Layout should facilitate editing and coding
The Art of Asking Questions Avoid complexity: use simple language n Avoid leading and loaded questions n ¨ Counterbiasing statement ¨ Split-ballot technique Avoid ambiguity: be as specific as possible n Avoid double-barreled items n Avoid making assumptions n Avoid burdensome questions that may tax the respondent’s memory n
Some Issues about Questionnaire Design n Order Bias ¨ Funnel technique ¨ Anchoring effect ¨ Filter question ¨ Pivot question n Best Layout ¨ Multiple-grid n question Pre-testing and Revising
Survey Research n Advantages of survey research: ¨ Quick ¨ Inexpensive ¨ Efficient ¨ Accurate
Survey Research Nonresponse error Random sampling error Respondent error Acquiescence bias Deliberate falsification Response bias Total Error Interviewer bias Unconscious misrepresentation Systematic error Data processing error Administrator error Extremity bias Sample selection error Interviewer cheating Auspices bias Social desirability bias
Experimental Research n n A research investigation in which conditions are controlled so that an independent variable(s) can be manipulated to test a hypothesis about a dependent variable. Allows evaluation of causal relationships among variables while all other variables are eliminated or controlled.
Summary Survey is a quantitative research tool because it can be quick, inexpensive, efficient, and accurate. n It’s important to reduce different types of errors during the survey. n
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