• Quasi-experimental design

A research design in which an experimental procedure is applied but all extraneous variables are not controlled

(always lack random assignment, does not meet all the requirements necessary for controlling the influence of extraneous variables)

Principles Used to Rule out Rival Explaations in Quasi Experiments

Number 1

Principles Used to Rule out Rival Explaations in Quasi Experiments

Number 2

Principles Used to Rule out Rival Explaations in Quasi Experiments

Number 3

Structures and procedures used in constructing research designs

1) control or comparison groups (zero, one, or more than one)

2) pretest (zero, one, or more than one)

3) posttest (one or more than one)

4) within-participants and /or between participants independent variables

5) inclusion of one or more theoretically interesting IVs

6) measurement of one or more theoretically interesting DV's

A quasi-experimental design in which the results obtained from nonequivalent experimental and control groups are compared.

(most common of all quasi-experimental designs, will not be equivalent on all variables)

Consists of giving an experimental and control group first a pretest and then posttest. Tests are compared to determine if significant differences exist. 

Selection bias--Because groups are nonequivalent, there will always be a potential selection bias. However, the pretest allows the exploration of the possible size and direction of the bias on any variables measured at pretesting.

Selection-attrition bias--The pretest allows examination of the nature of attrition to see if there is a difference between those that drop out or do not complete the experiment and those that do.

Selection-maturation bias--This might exist if one group of participants becomes more experienced, tired, or bored than those in the other group.

Selection-instrumentation bias--This might exist if the nonequivalent groups of participants start at different points on the pretest, particularly if the measuring instrument does not have equal intervals.

Selection-regression bias--This might exist if the groups are from different populations, such as the experimental treatment group from a population of individuals with a reading disability and the comparison group from a population of individuals without a reading disability.

Selection-history bias--This might exist if an event occurring between the pretest and posttest affects one group more than the other group.

• Assignment to comparison groups must be based only on the cutoff score
• The assignment variable must be at least an ordinal variable, and it is best if it is a continuous variable. It cannot be a nominal variable such as sex, ethnicity, religious preference, or status as a drug user or nonuser.
• The cutoff score ideally should be located at the mean of the distribution of scores. The closer the cutoff score is to the extremes, the lower the statistical power of the design.

Requirements of the Regression Discontinuity Design

(Continued)

• Assignment to comparison groups must be under the control of the eperimenter to avoid a selection bias. This requirement rules out most retrospective uses of the design.
• The relationship between the assignment and outcome variables (whether it is linear, curvilinear, etc.) must be known to avoid a biased assessment of the treatment effect.
• All participants must be from the same population. With respect to the regression discontinuity design, this means that it must have been possible for all participants to receive the treatment conditon. This means that the design is not appropriate, for example, if the experimental participants are selected from one school and control participants from another.

Twelve Major Characteristics of Qualitative Research

1st of 3 categories

 Design Strategies

1. Naturalistic inquiry--Studying real-world situations as they unfold naturally; nonmanipulative and noncontrolling; openess to whatever emerges (lack of predetermined constraints on findings).

2. Emergent design flexibility--Openness to adapting inquiry as understanding deepens and/or situations change; the researcher avoids getting locked into ridgid designs that eliminate responsiveness and pursues new paths of discovery as they emerge.

3. Purposeful sampling--Cases for study (e.g., people, organizations, communities, cultures, events, critical incidences) are selected because they are "information rich" and illuminative, that is, they offer useful manifestations, of the phenomenon of interest; sampling, then, is aimed at insight about the phenomenon, not empirical generalizations from a sample to a population

Twelve Major Characteristics of Qualitative Research

2nd of 3 categories

Data Collection and

Fieldwork Strategies

4.  Qualitative data--Observations that yield detailed, thick description; inquiry in depth; interviews that capture direct quotations, about people's personal perspectives and experiences; case studies; careful document review.

5.  Personal experience and engagement--The researcher has direct contact with and gets close to the people situatuion, and phenomenon under study; the researcher's personal experiences and insights are an important part of the inquiry and critical to understanding the phenomenon. 

6.  Empathic neutrality and mindfulness--An empathic stance in interviewing seeks vicarious understanding without judgement (neutrality) by showing openness, sensitivity, respect, awareness, and responsiveness; in observation it means being fully present (mindfulness).

7.  Dynamic systems--Attention to process; assumes changes as ongoing wheather focus is on an individual, an organization, a community, or an entire culture; therefore, mindful of and attentive to system and situation dynamics. 

Twelve Major Characteristics of Qualitative Research

3rd of 3 categories

Analysis Strategies

8.  Unique case orientation--Assumes that each case is special and unique; the first level of analysis is being true to, respecting, and capturing the details of the individual cases being studied; cross-case analysis follows from and depends on the quality of individual case studies. (authentic perspective)

9.  Inductive analysis and creative synthesis--Immersion in the details and specifics of the data to discover important patterns, themes, and interrelationships; begins  by exploring then confirming, guided by analytical principles rather than rules, ends with a creative synthesis.

10.  Holistic perspective--The whole phenomenon under study is understood as a complex system that is more than the sum of it's parts; focus on complex interdependencies and system dynamics that cannot meaningfully be reduced to a few discrete variables and linerar, casue-effect relationships. 

Twelve Major Characteristics of Qualitative Research

3rd of 3 categories

Analysis Strategies (continued)

11.  Context sensitivity--Places findings in a social, historical, and temporal context; careful about, even dubious of, the possibility or meaningfulness of generalizations across time and space; emphasizes instead careful comparative case analyses and extrapolating patterns for possible transferability and adaptation in new settings.(in terms of time).

12.  Voice, perspective, and relexivity--The qualitative analyst owns and is reflective about her or his own voice and perspective; a credible voice conveys authenticity and trustworthienss; complete objectivity being impossible and pure subjectivity undermining credibility, the researcher's focus becomes balance-understanding and depicting the world authentically in all its complexity while being self-anlytical, politically aware, and reflexive in consciouness.

Descriptions that are very close to particpants' words or are direct verbatim quotes.