Threats to validity

Tribhuvan University, Nepal
Masters in Arts
Population Studies
Research method in Population analysis
Validity and Threats to validity
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1. Validity and Threats to Validity Presented By: Roji maharjan Masters of Arts (T.U.) Population Studies Padma Kanya Multiple Campus

2. Objectives: To define validity To explain Methods of validity test along with its threats

3. Validity Validity is the extent to which a concept, conclusion or measurement is well-founded, accurately measuring what it’s supposed to and corresponds to real world. The term Validity means truth. Validity refers to the degree to which a test measure what is claims to measure. Validity means to measure with reasonable degree of Accuracy.

4. Methods of validity External Validity: - External validity is related to generalizing. -It is the degree to which the conclusions in study would hold for other persons in other places and at other times. -The variables used in the study are similar to those aspects as they exist in the larger population. - It occurs when the causal relationship discovered can be generalized to other people, time and contexts.

5. Threats to External validity: Selection Bias: The sample is not representative of the population. History: An unrelated event influences the outcomes. Experimenter effect: The characteristics or behaviors of the experimenter unintentionally influence the outcomes. Hawthorne effect: The tendency for participants to change their behaviors simply because they know they are being studied. Testing effect: The administration of a pre-test or post-test affects the outcomes. Aptitude-treatment: Interactions between characteristics of the group and individual variables together influence the dependent variable. Situation effect: Factors like the setting, time of day, location, researchers’ characteristics, etc. limit generalizability of the findings .

6. 2.Internal Validity It refers to the extent to which the results obtained in a research study are a function of the variables that systematically manipulated, measured, and observed in the study. It is the extent to which shows a cause-and-effect relationship established in a study cannot be explained by other factors. It is the approximate truth about inferences regarding cause-effect or causal relationships.

7. Threats To internal validity: History: the occurrence of events that could alter the outcome or the results. Maturation: any changes that occur in the subjects during the course of the study that are not part of the study and that might affect the results of the study. Instrumentation: concerned with the effects on the outcome of a study of the inconsistent use of a measurement instrument. Testing: the possible effects of a pre-test on the performance of participants in a study on the post-test. Statistical Regression: the tendency of extreme scores to move (or regress) toward the mean score on subsequent retesting. Mortality: the loss of subjects from a study due to their initial non-availability or subsequent withdrawal from the study. Selection: possibility that groups in a study may possess different characteristics and that those differences may affect the results.

8. Construct Validity It refers to the degree to which inferences can legitimately be made from the operationalizations in study to the theoretical constructs on which those operationalizations were based. The quality of choices about the particular forms of the independent and dependent variables.

9. Threats To Construct Validity: Mono-Operation Bias: it pertains to the independent variable, cause, program or treatment in study – it does not pertain to measures or outcome. Mono-Method Bias: it refers to your measures or observations, not to your programs or causes. Interaction of Different Treatments: Interaction of Testing and Treatment. Restricted Generalizability Across Constructs. Confounding Constructs and Levels of Constructs. The “Social” Threats Inadequate Preoperational Explication of Constructs. Hypothesis Guessing

10. 4.Conclusion Validity Conclusion validity is the degree to which conclusions we reach about relationships in our data are reasonable. It is relevant whenever we are trying to decide if there is a relationship in our observations. It is the degree to which the conclusion we reach is credible or believable.

11. Threats to conclusion validity: A threat to conclusion validity is a factor that can lead you to reach an incorrect conclusion about a relationship in your observations. low reliability of measures poor reliability of treatment implementation random irrelevancies in the setting random heterogeneity of respondents. low statistical power fishing and the error rate problem violated assumptions of statistical tests

12. Thank You!!