Research Instrument

1. The research instrument is very important in conducting a research study for the result will serve as the
basis in answering the research problem and selecting the correct hypothesis in the latter part of the
research. Thus, it is but right to consider the different scales in establishing a valid and reliable
instrument.
What makes a Good Research Instrument?
1. Valid and Reliable
 The instrument should measure what intends to measure.
 The instrument should have accuracy and consistency.
2. Usable
 The degree to which the tests are used without much expenditure of time, money and
effort. It also means practicability. Factors that determine usability are: administrability,
scorability, and economy.
3. Scorable
 A good instrument is easy to score thus: scoring direction is clear, scoring key is simple,
answer is available.
4. Economical
 One way to economize cost is to use answer sheet and reusable test.
 However, test validity and reliability should not be sacrificed for economy.
Types of Validity of Instruments
1. Construct validity
 This type of validity determines whether an instrument/measurement tool represents
the thing that the researcher wants to measure. Furthermore, construct validity ensures
that the measurement matches the construct that you want to measure. Construct
could be characteristics that the researcher intends to measure.
2. Content validity
 Content Validity evaluates whether an instrument covers all aspects of the construct.
This is very important in producing valid results. The researcher should always assure
that the instrument produced covers all relevant parts of the subject it aims to measure.
3. Face validity
 This considers how suitable the content of an instrument seems to be as it appears. It is
a subjective measure and considered as the weakest form of validity.
4. Criterion validity
 This type of validity evaluates how closely the result of your test to the result of other
tests conducted. Criterion refers to the external measurement of the same thing
Reliability of Instrument
1. Internal consistency reliability
 This type of test of reliability gauges how well an instrument is measuring what you
want to measure. This is very important for the researcher to ensure that they have
included sufficient number of items to capture the concept adequately.
2. Test-retest

2.  Measures the correlation between scores from one administration of an instrument to
another. This measures test consistency- the reliability of a test measured over time.
3. Inter-rater reliability
 Checks the degree of agreement among raters. This refers to the extent to which two or
more raters give consistent estimates of the same phenomenon.
4. Parallel Forms Reliability
 Used to assess the consistency of the results of two tests constructed in the same way
from the same content domain.