Students will evaluate the construct validity for the article “Effectiveness of solution focused therapy for affective and relationship problems in a private practice context.” This article is included here. The paper should be in Times New Roman, 12 point font and adhere to APA 6th Ed. guidelines. No abstract is needed. The paper should be 2pages
Internal validity (IV) is associated with the cause and effect statements researchers make. IV is the main aspect of the methods researchers use in a study. Internal Validity is concerned about making cause and effect claims based on the research design of a study. Hopefully, the design will eliminate revival hypotheses. Intimately related to the amount of experimental control: (1) Random selection of participants, (2) Random assignment to groups control and experimental, (3) Manipulation and measurement of variables, and (4) Timing of measurements.
There are three main types of designs research. They are: (1) One shot pretest/posttest designs, (2) non-equal groups, and (3) equal groups designs. Remember that non-equal and equal groups are different based on random selection. Researchers specify which participants are in the treatment and control (no treatment) groups in non-equal designs. Random selection is used in equal designs.
Step 1: Identify the causal statements
To determine the threats to internal validity, one must discern the causal statements made
Identify the research design that is used to control for alternative explanations
Step 2: Identify researchers methods of ruling out alternative explanations
Step 3: Evaluate the causal statements using the 13 threats to internal validity
History: any event that may effect the participants and offer alternative explanations for the differences between groups
Maturation: The effects of normal developmental processes that impact the differences observed between pre and posttests
Testing: Increases or improvements in scores due to familiarity with test, Recall of previous items, Only an issue when giving both a pre and posttest
Instrumentation: The scoring of the measures used may change systematically, The use of error of measurement, All instruments are vulnerable to this threat
Statistical regression: Often called regression toward the mean, Outliers often regress toward the mean over the course of observations, Major issues concern critical cutoff scores, i.e. using the clinical level of the DAS to determine level of dysfunction and amount of therapeutic improvement
Attrition or mortality: This occurs when participants drop out of the study, This may introduce systematic biases in the remaining participants
Interaction with selection: Participating in the study may interact synergistically with the other threats to internal validity
Ambiguity regarding direction of causal influence
Diffusion or imitation of treatments: This occurs when treatment effects are spread inadvertently to the control group, This removes group differences even when there may be significant differences
Compensatory equalization of treatments: Participants in the control group are provided extra services as a result of their placement in the control group
Compensatory rivalry by control group participants: Occurs when members of the control group try to beat the members of the treatment group
