Sampling/ Qualitative Research The Curious Skeptics Still at Work

Today’s Goals Evaluate sampling procedures for quantitative and qualitative studies. Know when to use qualitative research

Quick Review What is empirical research? Differences between qualitative and quantitative research What is action research? Purpose of literature review Hypothesis Variables

Sampling Procedures Two types of procedures –Probability Statistically driven sampling techniques where the probability of being selected is known Purpose is to select a group of subjects representative of the larger group of subjects from which they are selected –Non-probability (purposive) Pragmatically driven sampling techniques where the probability of being selected is not known Purpose is to select subjects who can be particularly informative about the research issues

Sampling Procedures Qualitative uses ______ sampling. Quantitative uses ______ sampling. –Qualitative uses non-probability sampling. –Quantitative uses both. Convenience sampling is often used in educational and psychological research. Problem = generalizability.

Probability Sampling Population (also “target population”) –Large group of individuals to whom the results of a study can be generalized Sample –Subgroup drawn from the population –Should be representative of total population

Probability Sampling 2 ways to muck it up –Sampling error - the difference between the “true” result and the “observed” result that can be attributed to using samples rather than populations –Sampling bias - the difference between the “observed” and “true” results that is attributed to the sampling mistakes of the researcher

Thought Question How can use of volunteers skew results? –Volunteers may have certain characteristics like higher motivation, be in a higher socio-economic demographic, desire social approval.

Probability Sampling Types of probability techniques –Simple random – –Systematic - every n th member –Stratified sampling Proportional – be careful of large enough N Disproportional –Cluster – ex. school district

Sampling and Results Sample size - general rules of thumb –Quantitative –Quantitative studies correlational30 subjects for correlational research experimental15 subjects in each group for experimental research surveyApproximately 250 responses for survey research

Qualitative Research: Purposive Sampling Use of purposeful sampling strategies to select “information rich” participants Not intended to be representative of larger population! (i.e., not random sampling). Contrast with most quantitative studies. Be clear about why selecting participants or state “convenience sampling”

Purposive Sampling Strategies –Maximum variation - selecting individuals or cases to represent a full range of characteristics –Snowball (i.e. network) - initially selected participants recommend others for involvement

Selecting Participants Strategies –Sampling by case - selecting individuals or cases for their unique characteristics Extreme Typical –Key informant - selecting an individual(s) particularly knowledgeable about the setting and/or topic –Comprehensive - selecting all relevant individuals or cases

Sampling and Results Sample size - general rules of thumb –Qualitative –Qualitative studies - a sufficient number of subjects are needed to ensure that no new information is forthcoming from additional cases (“saturation”)

Terms, terms, terms Create a concept map with the following terms. (Add terms if necessary.) –Quantitative Sampling – Simple Random Sampling –Qualitative Sampling – Stratified Random Sampling –Convenience Sampling – Purposive Sampling –Systematic Sampling – Cluster Sampling –Typical Case Sampling – Extreme Case Sampling –Maximum Variation Sampling – Snowball Sampling –Sample – Target Population –Biased Sampling – Sampling Error –Sample Size

Qualitative Research Problems When to use a Qualitative design –To understand a phenomenon about which little is known (exploratory) –To gain a novel slant about a phenomenon we do know about (novelty) –To obtain greater detail about phenomenon that are difficult to understand through solely quantitative methods (process)

Qualitative Research Problems Identifies a central phenomena (i.e., an issue or process) being investigated –Examples of issues Drug abuse in high schools Teacher burnout Alienation of children with special needs –Examples of processes How teachers change to standards-based curricula How students react to high stakes testing programs How students incorporate teachers’ expectations into their studies

Qualitative Research Problems Characteristics –Includes a single, central phenomena –Open-ended –General in nature –Emergent –Neutral with respect to what will be learned No hypotheses, but still may have “hunches” Open to new information No expected outcomes

Sample Research Questions “How do students at an alternative school for students at-risk of dropping out of school perceive their learning environment?” “What changes do teachers and counselors make when their school is placed on probation under the No Child Left Behind Law? What remains the same?”

Qualitative Data Collection Interviews Observations Document Analysis

Interview Protocols Rapport Unstructured in nature, yet have focus General (“grand tour”) questions to specific questions based on participant responses Tape recording and transcribing interviews afford the opportunity to study the data carefully

Observations Unstructured in nature, yet have focus Participant-observer role of the researcher –Continuum between observer and participant Complete ObserverParticipantComplete ObserverParticipantObserverParticipant –This should be clear in the study!

Next Class Bring Orcher – Chapter 9, 19 Bring highlighters (multiple colors if you have them). We’re going to analyze data!!