QUESTION
Write a note on content validity and content construct validity.
Course: Educational Assessment and Evaluation
Course code 8602
Level: B.Ed Solved Assignment
Course code 8602
Level: B.Ed Solved Assignment
ANSWER
Content Validity
The evidence of the content
validity is a judgmental process and may be formal or informal. The formal
process has a systematic procedure which arrives at a judgment. The important
components are the identification of behavioural objectives and the construction of a table of specifications. Content validity evidence involves the degree to which the
content of the test matches a content domain associated with the construct. For
example, a test of the ability to add two numbers should include a range of
combinations of digits.
A test with only one-digit numbers, or only even numbers, would not have good coverage of the content domain. Content-related evidence typically involves Subject Matter Experts (SMEs) evaluating test items against the test specifications. It is a non-statistical type of validity that involves “the systematic examination of the test content to determine whether it covers a representative sample of the behaviour domain to be measured” (Anastasi & Urbina, 1997). For example, does an IQ questionnaire have items covering all areas of intelligence discussed in the scientific literature? A test has content validity built into it by careful selection of which items to include (Anastasi & Urbina, 1997). Items are chosen so that they comply with the test specification which is drawn up through a thorough examination of the subject domain. Foxcraft et al. (2004, p. 49) note that by using a panel of experts to review the test specifications and the selection of items the content validity of a test can be improved.
The experts will be able to
review the items and comment on whether the items cover a representative sample
of the behaviour domain.
For
Example –
In developing a teaching
competency test, experts in the field of teacher training would identify the
information and issues required to be an effective teacher and then choose
(or rate) items that represent those areas of information and skills which are
expected from a teacher to exhibit in the classroom.
Lawshe
(1975) proposed that each rater should respond to the following question
for each item in content validity: Is the skill or knowledge measured by this
item?
• Essential
• Useful but not essential
• Not necessarily Concerning educational achievement tests, a test is considered content valid when the proportion of the material covered in the test approximates the proportion of material covered in the course.
Construct Validity
Before defining the construct validity, it seems necessary to elaborate on the concept of the construct. It is the concept or the characteristic that a test is designed to measure. A construct provides the target that a particular assessment or set of assessments is designed to measure; it is a separate entity from the test itself. According to Howell (1992), Construct validity is a test’s ability to measure factors which are relevant to the field of study. Construct validity is thus an assessment of the quality of an instrument or experimental design. It says 'Does it measure the construct it is supposed to measure'. Construct validity is rarely applied in achievement tests.
Construct validity refers to the
extent to which operationalizations of a construct (e.g. practical tests
developed from a theory) do actually measure what the theory says they do. For
example, to what extent is an IQ questionnaire actually measuring
"intelligence"? Construct validity evidence involves the empirical
and theoretical support for the interpretation of the construct. Such lines of
evidence include statistical analyses of the internal structure of the test
including the relationships between responses to different test items. They also
include relationships between the test and measures of other constructs. As
currently understood, construct validity is not distinct from the support for
the substantive theory of the construct that the test is designed to measure.
As such, experiments designed to reveal aspects of the causal role of the
construct also contribute to construct validity evidence. Construct validity
occurs when the theoretical constructs of cause and effect accurately represent
the real-world situations they are intended to model. This is related to how
well the experiment is operationalized. A good experiment turns the theory
(constructs) into actual things you can measure. Sometimes just finding out
more about the construct (which itself must be valid) can be helpful.
The construct validity addresses
the construct that is mapped into the test items, it is also assured either by the judgmental method or by developing the test specification before the
development of the test. The constructs have some essential properties the two
of them are listed as under: 1. Are abstract summaries of some regularity in
nature? 2. Related with concrete, observable entities. For Example - Integrity
is a construct; it cannot be directly observed, yet it is useful for
understanding, describing, and predicting human behaviour.
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