Exam 1 - Study Material (Quiz 2) Flashcards
What is the purpose of research design?
- Provides blueprint/plain - this aids in solving problem/question/hypothesis
- Allows researcher to apply different levels of control
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We do all of this to say:
- Independent variable really changed the dependent variable and not something else
- To avoid bias
What should you consider when planning “control” in a study?
- Objectivity
- Accuracy
- Feasibility
- CONTROL & FIDELITY
What are some things that affect “control & fidelity” of a deisgn?
- Homogenous sample
- Constancy – Intervention fidelity
- Manipulation
- Randomization
- Validity- Internal
- Validity-External
What is the purpose for control in a study?
- To control for bias
- To ensure Accuracy- Pilot study
- You want to make sure the independent variable really lead to the change in dependent variable and not another variable
What is an Antecedent Variable?
Variables that occur within the subjects prior to the study.
Ex: A patient’s motivation to learn about their medical condition might affect how successful a diabetes education program is for him/her.
What is a ®Intervening, Extraneous or Mediating Variable?
A variable (which the reasearcher doesn’t control) that occurs between the Independent and dependent variable (such as age, gender, diet,etc), and it interferes with the operations of the variables being studied.
Ex: The type of breast cancer treatment patients expereienced.
Describe homogeneous sampling
Sampling that occurs when the researcher’s subjects have similar extraneous variables relevant to the particular study (within the same age group, same gender, etc)
What is generalizability?
Being able to apply research outcomes to other populations when analyzing and discussing the outcomes.
What is Intervention Fidelity in relation to control in a study?
Intervention fidelity involves having consistency in:
- Design - The study is designed to allow an adequate testing of the hypothesis in relation to the underlying theory and clinical processes
- Training - Ongoing training and supervision of the data collecters to assure that the intervention is being delivered as planned and in a similar manner with all subjects
- Delivery - Assessing the intervention is delivered as intended, including that the “dose” is well described for all subjects and that the dose is the same in each group, and that there is a plan for possible problems.
- Receipt - Assurance that the treatment has been received and understood by the subject
- **Enactment - Assessment that the performance of the intervention skills that the subject performs are performed as intended **
What is manipulation in relation to control?
- The addministration of a treatment, program or intervention to only one group within the study and not to the other subjects in the study to test whether a treatment or intervention affects patient outcomes.
- This leads to the creation of the Experimental (the group in which the independent variable is changed) and the control Group (where everything is held constant)
What is randomization in relation to control?
Subjects from the population are obtained in such a manner that each subject has an equal and independent chance of being selected for either group.
This eliminates bias and helps make a representative sample
What are the elements of a research design?
- Participants (WHO)
- Observations (WHAT)
- Selection of subjects (WHERE)
- Role of the investigator
What is internal validity?
- It is the degree to which it can be inferred that the experimental treatment, rather than an uncontrolled condition, resulted in the observed effects
- It asks if it is the independent variable (or something else) that caused or resulted in the chagne in the dependent variable
What are some threats to internal validity?
- History bias
- Selection bias
- Maturation bias
- Testing bias
- Mortality bias
- Instrumentation bias
What is the “history bias” threat to internal validity
It is a specific event outside the study that affects subjects and thus the study results
Ex: An investigator testing the effects of an educational program for young adults on completion of organ donation card designations. During the course of the educational program, an ad featuring a known public figure is released on facebook about he importance of organ donation and becoming an organ donor. The occurence of this information on social media with a public figure engenders a great deal of media and press attention. If the researcher finds an increase in the number of young adults who sign their organ donation cards, the researcher may not be able to conclude that the change in behavior is the result of the teaching program because it may have been influenced by the result of the information on social media.
What is the “selection bias” threat to internal validity?
It is the internal validity threat that arises when pretreatment differences between the experimental group and the control group are present.
Ex: This can occur if the sample was not random or representative of the population being studied, like if a smoking cessation program allowed self-selection of the control or experiemental group
What is the “maturation bias” threat to internal validity?
Developmental, biological or psychological processes that occur within subjects that are independent of the intervention or study variables.
Ex: In a study of new products to stimulate wound healing, one might ask wherther the healing that occured was related to the product or to the natural occurance of wound healing.
What is the “testing bias” threat to internal validity?
It is the effect that occurs from taking the same test repeatedly, influencing a subject’s responses the next time the test is completed.
Ex: Individuals generally score higher when they take a test a second time, regardless of the test.
What does “mortality” refer to in quantitative research?
It is the loss of study subjects from the first data-collection point (pretest) to the second data-collection point (post test)
What is the “mortality bias” threat to internal validity?
This bias can occur if the subjects who remain in the study are not similar to those who dropped out, affecting the results of the study.
Ex: A group of reserachers noted that they had lost subects in all 3 of their groups, and that the lack of statistical significance in their findings may have been related to an inadequate sample size even though the intervention had a positive outcome
What does “instrumentation bias” refer to in quantitative research?
A change in the instruments themselves OR change in the data collection procedures that may account for change in the dependent variable.
Ex: A researcher may wish to study types of thermometers to compare the accuracy of using a tympanic thermometer to other temperature-taking methods. A researcher must check the calibration of the termometers according to the manufacturer’s sepcifications before and after data collection
What is external validity?
- It is the degree to which findings of a study can be generalized to other populations or envrioments
- It questions under what conditions and with what types of subjects can the same results be expected to occur
What are some threats to external validity?
- Selection effects (who)
- Reactive effects (Where-how)
- Measurement effects (How-when-what)
What is “selection” in relation to a quantitative study?
The generalizability of the results to other populations







