This document discusses different types of validity in testing, including external validity, internal validity, population validity, and ecological validity. It defines validity as the extent to which a test measures what it claims to measure. The document also lists 11 potential problems that can threaten internal validity in experimental research, such as history effects, maturation effects, testing effects, instrumentation effects, and selection biases. Maintaining internal validity is important so that any differences observed are due to the independent variable rather than other confounding factors.

1. Topic: Validity of Problems
The Islamia University of
Bahawalpur
Muhammad Khizer Hayat
Khaleel Ahmad
Session: 2016-18 (Spring)
Semester: 3rd
Supervised By: Dr.Fakhra Shamim

2. Def:
“Validity is the extent to which a test measures what it claims to
measure. It is vital for a test to be valid in order for the results to
be accurately applied and interpreted.”
Types of Validity:
External Validity:
It is the extent to which the results of a research study can be generalized to
different situations, different groups of people, different settings, different
conditions, etc.
Internal Validity:
It is basically the extent to which a study is free from flaws and that any
differences in a measurement are due to an independent variable and
nothing else.
Population Validity:
It refers to the extent to which the findings can be generalized to other
populations of people.
Ecological Validity:
It refers to the extent to which the findings can be generalized beyond the
present situation.

3. • Problems:
•
• 1. History:- events that occur besides the treatment (events in the
environment).
• 2. Maturation:- physical or psychological changes in the participants.
• 3. Testing:-effect of experience with the pretest - - become test wise.
• 4. Instrumentation:- learning gain might be observed from pre to posttest
simply due to nature of the instrument. Particularly a problem in
observation studies when observers more likely to give ratings based on
expectations (conscious or subconscious).
• 5. Statistical Regression:-Tendency for participants whose scores fall at
either extreme on a variable to score nearer the mean when measured a
second time.
• 6. Differential Selection:-Effect of treatment confounded with other factors
because of differential selection of participants, problem in non random
samples.
• 7. Experimental Mortality:-participants lost from the study, attrition.

4. 8. Selection-maturation Interaction:- similar to differential selection,
except maturation is the confounding variable.
9. Experimental Treatment Diffusion:-Treatment is perceived as highly
desirable and members of control group seek access.
10. Compensatory Rivalry by Control Group:- (John Henry Effect) - - control
group performs beyond expectations because they perceive they are in
competition with experimental group.
11. Compensatory Equalization of Treatments:- occurs when experimental
group received goods or services perceived as desirable and control group is
given similar goods and services on compensate. Not comparing treatment with
no treatment but one treatment with another.
12. Resentful Demoralization of Control Group:- Control group becomes
discouraged because they perceive experimental group is receiving a desirable
treatment that is being withheld from them.