What makes a research instrument is reliable?

Reliability refers to how consistently a method measures something. If the same result can be consistently achieved by using the same methods under the same circumstances, the measurement is considered reliable. You measure the temperature of a liquid sample several times under identical conditions.

How can you tell if an instrument is valid?

An instrument is content valid when the items adequately reflect the process and content dimensions of the objectives of the instrument (Benson & Clark, 1982). Again, the instrument should be distributed to a sample that is representative of the target group.

How do you ensure reliability of research instruments?

The same instrument is given twice to the same group of people. The reliability is the correlation between the scores on the two instruments. If the results are consistent over time, the scores should be similar. The trick with test-retest reliability is determining how long to wait between the two administrations.

Why is the reliability of an instrument important?

Think of reliability as consistency or repeatability in measurements. Not only do you want your measurements to be accurate (i.e., valid), you want to get the same answer every time you use an instrument to measure a variable. This makes reliability very important for both social sciences and physical sciences.

What makes an instrument valid?

Validity refers to the degree to which an instrument accurately measures what it intends to measure. Content validity indicates the extent to which items adequately measure or represent the content of the property or trait that the researcher wishes to measure.

How can an instrument be reliable but not valid?

A measure can be reliable but not valid, if it is measuring something very consistently but is consistently measuring the wrong construct. Likewise, a measure can be valid but not reliable if it is measuring the right construct, but not doing so in a consistent manner.

What will happen if the instrument is valid but not reliable?

An instrument must be reliable in order to be valid. For an instrument to be valid, it must consistently give the same score. However, an instrument may be reliable but not valid: it may consistently give the same score, but the score might not reflect a person’s actual score on the variable.

What makes the assessment instrument valid and reliable?

Assessment instruments must be both reliable and valid for study results to be credible. Thus, reliability and validity must be examined and reported, or references cited, for each assessment instrument used to measure study outcomes.

What are the qualities of good test instruments?

Characteristics of good measuring instrument:

• RELIBILITY. RELIBILITY – is the consistency of your measurement, or the degree to which an instrument measures the same way each time it is used under the same condition with the same subjects.
• VALIDITY.
• PRACTICIBILITY.
• USABILITY.
• MEASUREABILITY.

What are some qualities of a good test?

Top 4 Characteristics of a Good Test

• Characteristic # 1. Reliability:
• Characteristic # 2. Validity:
• Characteristic # 3. Objectivity:
• Characteristic # 4. Usability:

Why is it important to have a good research instrument?

The conclusions drawn in a research study are only as good as the data that is collected. A poorly designed instrument will lead to bad data, which will lead to bad conclusions. Therefore, developing a good instrument is the most important part of conducting a high quality research study.