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The Experts Behind The Ex Post Facto Research Design

❶Pretest — A test administered prior to a specific treatment or intervention. They provide a systematic approach to the process of historical research.

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Recommendations in the life care plan must be supported by research data and based upon the documented course of disability and patient-specific variables over time. The manner in which a researcher designs a study determines the type and depth of information which can be concluded from the project.

For this reason, researchers spend a significant amount of time considering the most effective design in addressing the topic of interest. First, a researcher determines the purpose of the study. Are they seeking to:. Then surveys, case studies, and developmental studies may be most appropriate. Then relational, associational, correlational, or ex post facto designs may be most effective.

Then experimental or quasi-experimental are likely to yield the most useful results. Descriptive research designs are most effectively applied to studies aimed at gathering additional information, learning more about an area of interest, or becoming more familiar with a topic. Researchers interested in identifying the prevalence or incidence of a disability or in describing the distribution and characteristics of a group of patients may adopt a descriptive research design.

Typically, a researcher gathers information from a large group of participants either by mail, interactive online site, telephone interview, or personal interview. A survey does not investigate relationships between variables, patient-specific characteristics, or generalize findings to all members of a population. In other words, the purpose of survey research is not to establish cause and effect relationships. Most individuals have completed a survey of some type, whether a public opinion questionnaire, customer service form, or community investment poll.

Developmental studies generally follow a group of participants over time and document changes in status. These types of studies may be referred to as trend, cohort, or panel designs.

In most cases, researchers collect data at specific points in time which are used as a basis of comparison and analysis. Narrative or documentary-style reports may result from this type of design, but conclusions cannot be applied to other members of the target population.

Developmental studies are useful in describing phenomena longitudinally and may be used as the foundation for further investigation. The purpose of this type of research is the same as pursued by survey and developmental designs, but generally involves much smaller sample sizes. Rather than gathering information from a large group of people, as in survey designs, the researcher is interested in gaining deeper insights into a fewer number of subjects. This form of inquiry typically involves personal interview or direct observation throughout the data collection process.

Examples of this type of design may be a study based on the relationships and interpersonal dynamics of a specific family, documenting the experiences of a small group of patients with traumatic brain injury in a rehabilitation facility, or observing the interactions of selected toddlers in a preschool setting.

The purpose of relational or associational research is to identify the relationship or association between two or more variables. The purpose is not to establish cause and effect but to:. There are two types of correlational studies; concurrent and predictive. Concurrent correlational studies involve assessment of the relationship between characteristics that were collected by the researcher at the same point in time. Predictive correlational studies may be utilized when a researcher is interested in determining whether knowing a previously documented characteristic or set of characteristics can lead to the prediction of a later characteristic or set of characteristics.

This type of design is often utilized when it is not possible to control the experience, exposure, or influences which may affect participants. The purpose of experimental or quasi-experimental research is to establish a cause and effect relationship between two variables. Maturation , processes within the participants as a function of the passage of time not specific to particular events , e.

Testing , the effects of taking a test upon the scores of a second testing. Instrumentation , changes in calibration of a measurement tool or changes in the observers or scorers may produce changes in the obtained measurements. Statistical regression , operating where groups have been selected on the basis of their extreme scores. Selection , biases resulting from differential selection of respondents for the comparison groups. Experimental mortality , or differential loss of respondents from the comparison groups.

Selection-maturation interaction , etc. Four factors jeopardizing external validity or representativeness are:. Reactive or interaction effect of testing , a pretest might increase. Interaction effects of selection biases and the experimental variable. Reactive effects of experimental arrangements , which would preclude generalization about the effect of the experimental variable upon persons being exposed to it in non-experimental settings.

Multiple-treatment interference , where effects of earlier treatments are not erasable. You can use this presentation to help improve the quality of your answers for the exam which is due April 9. White Plains, New York: Analysis of Professional Literature Class 4: James Neill Last updated: What you should keep in my mind is that there are two key, current applications for developing your knowledge about quantitative research design: Types of Designs Bill Trochim Reading: Basic Issues in Research Design Reading: Experimental Design Bill Trochim Reading: Eight extraneous variables can interfere with internal validity: History , the specific events occurring between the first and second measurements in addition to the experimental variables 2.

Reactive or interaction effect of testing , a pretest might increase

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Ex post facto design is a quasi-experimental study examining how an independent variable, present prior to the study in the participants, affects a dependent variable. A quasi-experimental study simply means participants are not randomly assigned.

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treatments to determine differences in the dependent variables, an ex post facto experiment begins with groups that are already different in some respect and searches in retrospect for factors that brought about those differences. In this way, ex post facto research can transform a non-experimental research design into a pseudo-experimental. study.

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Ex post facto study or after-the-fact research is a category of research design in which the investigation starts after the fact has occurred without interference from the researcher. The majority of social research, in contexts in which it is not possible or acceptable to manipulate the characteristics of human participants, is based on ex post facto research designs. 2 Robert S Michael Correlation & Ex Post Facto designs-3 Causal Comparative Research Involves comparison of two or more groups on a single endogenous variables. The characteristic that differentiates these groups is the exogenous variable. Causal comparative studies are also called ex post factobecause the investigator has no control over the.

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Designing Research: Ex Post Facto Designs MAUREEN GIUFFRE, PhD, RN The research design is the overall plan or structure of the study. The goal. An ex post facto research design is a method in which groups with qualities that already exist are compared on some dependent variable. Also known as "after the fact" research, an ex post facto design is considered quasi-experimental because the subjects are not randomly assigned - they are grouped based on a particular characteristic or trait.