Dear Program Evaluation Students
There are few very important things. First I haven't seen any comments from Program Evaluation students on blog. Second, I am interested to know your understanding on threats to validity. Do write what you have understood!
I will appreciate if students those have rights to start a thread should start the threads.
Lastly, Happy Eid Mubarik !
there are the following threats to validity.
ReplyDeleteconfounding
selection
history
maturation
Greatest threat is Confounding when it makes us blind to the establish a causal relationship.
ReplyDeleteThen there are so-called "weaker threats"
1. History; when an outside event effects the dependent variable.
2. Selection; this can be a threat if there is no randomness in choosing the target.
3. Maturation; can be threat if there are internal changes in the subjects.
4. Instrumentation; can be a threat if there are changes in the instruments used for measurement.
And, Eid Mubarik.
Greatest threat is Confounding when it makes us blind to* establish a causal relationship.
ReplyDeletea lil typo there.
Besides what has already been mentioned, and confounding being the greatest threat, there are the following threats to validity;
ReplyDeleteInstrumentation,
Selection,
Subject Morality,
Testing,
Maturation,
History.
Eid Mubarak to all!!!
ReplyDeleteSenior fellows have rightly described the "Threats to Validity", I will add here some more, in order to complete the details of the topics.
Point No. 1
Suppose we are evaluating something and there is no comparison group in study, then we must take into mind the following threats;
History
Maturation
Testing
Instrumentation
Selection
and Regression
Regression means here the "Chance factor" for instance some times people do very well or some times depict very poor performance if we consider "luck" as Chance Factor.
Point No. 2
If some comparison group occur then we must also consider another threat to validity which is;
Additive Effects
This means that if one of the group of participants responds differently to External Event (History), and it subsequently matures differently (Maturation)or is measured differently with the sensitive sophisticated instrument (Testation), then these all threats in the end result into Additive Effects and accounts for group differences in the end.
P.S. Sir it once again requested to you kindly give me the rights to start a thread on this blog and obliged. Thanks.
Mohib.
Beside, there are three major threats to external validity because there are three ways you could be wrong
ReplyDeletepeople
place
time
Social threat to internal validity: threat that arise because social research is conducted in real world human context where people will react to not only what effects them but also to what is happening around them.