Janice Long, PhD, RN Patricia Hart, PhD, RN Definition of Design - - PowerPoint PPT Presentation
RESEARCH DESIGNS Janice Long, PhD, RN Patricia Hart, PhD, RN Definition of Design Research design is the master plan that guides and holds together all the major parts of the research project to address the central research questions.
Research Problem/Question Data Methods
measures used
Trochim & Donnelly, 2009
Threat What it means What kind of study is most likely to be effected Strategies
Temporal Ambiguity Is the independent variable really coming before the dependent variable Comparative & correlational designs Understanding of the variables under study History The occurrence of external events that take place concurrently with the IV, and that can affect the
Longitudinal & Repeated Measures studies. Randomization Control group Maturation Processes occurring within participants during the course of the study as a result of the passage of time rather than as a result of the IV. Participants get older, wiser, more depressed, more hungry, more tired. Longitudinal studies where the participants are more likely to change such as adolescents, infants, or people who are quite ill. Randomization Control group
Threat What it means What kind of study is most likely to be effected Strategies
Testing Occurs when a pretest influences the way subjects respond on a post test. Repeated measures or a pre- test-post-test design Control group Instrumentation Changes made in the way the variable is measured, i.e, BP. Data collectors get better or worse at what they are doing. Physiologic instruments or those in which researchers are collecting the data in person. Regular calibration, use of multiple observers, training of observers establishment of reliability, validity, and objectivity of measurement procedures
Threat What it means What kind of study is most likely to be effected Strategies
Selection Pre-existing differences between the participants selected for a study or those who volunteer for the study & those not in the study. Quasi-experimental studies and convenience samples. Random selection Random assignment Control group Mortality/Attrition Participants drop out of a study or are lost to follow up Longitudinal studies. Subject matching &
Threat What it means What kind of study is most likely to be effected Strategies
Reactivity The influence of participating in a study on the responses of subjects. (Hawthorne effect: Participants’ behaviors affected by personal values or desires t please the experimenter). Researcher may inadvertently affect how intervention conducted or how they interact with participants. Any study with pre-test. Inform the subjects
Double-blind experimental designs Effects of Selection Sample does not reflect the general population Convenience samples Randomization
Threat What it means What kind of study is most likely to be effected Strategies
Interaction of Treatment & Selection of Subjects Where the independent variable might not affect individuals the same way Convenience samples Random selection Random assignment Control group Subject matching Interaction of Treatment & Setting When the intervention in
generalized using the same intervention Studies related to the same phenomenon which used similar types of hospitals Use diverse sample populations when conducting studies Interaction of Treatment & History When external events affect the intervention Studies in which the intervention is likely to have changed or the targeted populations may have changed Randomization Control group Replication studies