What is Reliability?
Reliability refers to the consistency
of a measure. A test is considered
reliable when we get the same result
repeatedly. It is impossible to
calculate reliability exactly, but it
can be estimated in a number of a
Errors of measurement
Test-Takers- this sources of errors
takes place into consideration what is
happening within the individual like
fatigue, hunger, headache, emotional
upset and anxiety growth.
Test- Administration- it can be cause
by lighting of examination room, room
temperature, noise, sitting
arrangement, instruction, attitude of
Test- Scoring- factors that contribute
to error in scoring include miskey,
wrong answer to test items, mistake in
correcting answer, mistake in the use
of correcting pencil and subjective
Test Itself- the difficulty of the test,
may contain poorly constructed items
that gives clues, ambiguous items, very
easy items and very difficult.
Expert agree that the longer the test the
higher is its reliability.
Different Methods Of
Test-Retest Reliability- the test is
administered twice at two different
points in time. It is best use for
things that are stable over time.
Inter-rater Reliability- assess by
having two or more independent
judges score the test. The score has
been compared to determine the
consistency of the raters estimate.
Parallel Forms Reliability- gauged by
comparing two different test that were
created using the same content.
Internal Consistency Reliability- use to
judge the consistency of results across
items on the same test. When we see a
question that seems very similar to
another test question. It may indicate
that two questions are being use the
Split-half- give parallel form of test
with in crease time interval between
forms using Pearson R formula.
Kuder Richardson- give the test
once then correlate the proportion
and percentage of the student
passing and not passing a given
items with the measure of internal