Testing: Reliability, Validity and Practicality

How do you know if a test is effective? if you want to know the answer to that questions, you have to respond these questions about the test itself:

  1. Can I apply the test within appropriate administrative constraints?
  2. Does the test measure what you are trying to measure?
  3. Can the test be score by different teachers and yield similar results?

If you can answer positively to those three and other related questions, your test is an effective test or in other words your test is reliable, practical and valid.

Reliability in Assessment

A reliable test means that it should give the same results for similar groups of students and with different people marking.

  1. Keep the instruction language simple and give an example.
  2. Use language that is similar to what you’ve used in class, so as not to confuse students.
  3. If possible, ask a colleague to do the test before you use it with students.
  4. For testing productive skills such as writing and speaking, have two markers and use standard written criteria.
  5. Administer the test to the same group of individuals on two separate occasions and analyze the correlation between their scores to assess test-retest reliability.
  6. Conduct item analysis to identify and remove items that are consistently problematic or do not contribute to the overall reliability of the test.

There are factors that contributes to the unreliability of a test such as:

  • Student-related reliability which can be caused by fatigue, sickness, anxiety.
  • Rater Reliability which can be caused by subjectivity, bias and human error
  • Test Administration Reliability which can be caused by the conditions in which a test is administered
  • Test Reliability which is caused by the nature of a test. Long tests can cause fatigue

Validity in Assessment

Validity is the extent to which a test measures what it claims to measure. To make a valid test, you must be clear about what you are testing.

Always test what you have taught and can reasonably expect your students to know.

Check these two examples that illustrate the concept of validity well.

  • To test writing with a question where your students don’t have enough background knowledge is unfair.
  • Testing speaking where they are expected to respond to a reading passage they can’t understand will not be a good test of their speaking skills.

These are some recommendations to ensure a test is valid:

  1. Clearly Define the Construct: Begin by clearly defining what the test is intended to measure.
  2. Expert Review: Have subject matter experts review the test items to ensure they are appropriate and relevant to the construct being assessed.
  3. Pilot Testing: Pilot test the items with a small sample of individuals to gather feedback on the clarity, relevance, and appropriateness of the items.

Practicality in Assessment

Practicality in assessment means that the test is easy to design, easy to administer and easy to score.

No matter how valid or reliable a test is, it has to be practical to make and to take this means that:

  1. It is economical to deliver. It is not excessively expensive
  2. The layout should be easy to follow and understand.
  3. It stays within appropriate time constraints
  4. It is relatively easy to administer
  5. Its correct evaluation procedure is specific and time-efficient

Characteristics of impractical tests are:

  1. These test are excessively expensive
  2. They are too long
  3. They require a handful of examiners to administer and score
  4. It takes several hours to grade a test

Keep these recommendation in mind to make sure your test are easy to design, easy to administer and easy to score:

  • Length of Test: Keep the test length manageable to avoid fatigue or disengagement among participants.
  • Scoring Procedures: Develop clear and efficient scoring procedures to minimize errors

Practice Time: Reliability, Validity and Practicality


Read the sentences and identify if they refer to reliability, validity and practicality

  1. “This aspect of a test ensures that it consistently produces the same results when administered multiple times.”
  2. “It concerns whether a test accurately measures what it claims to measure.”
  3. “This factor evaluates how feasible and efficient it is to use a test in real-world situations.”
  4. “When a test accurately represents the content domain it intends to measure, it is said to have this characteristic.”
  5. “This term refers to the stability and consistency of a test’s results over time and across different administrations.”
  6. “Considering the cost, time, and ease of administration of a test, we are discussing its…”
  7. “If a test consistently produces different results for the same individual across different administrations, it lacks this important aspect.”
  8. “When a test accurately predicts future performance or outcomes, it demonstrates this quality.”
  9. “This aspect of a test considers how well it aligns with the theoretical construct it aims to measure.”
  10. “Ease of scoring, administration, and interpretation are key considerations for assessing this aspect of a test.”

Manuel Campos, English Professor

Manuel Campos

I am Jose Manuel, English professor and creator of EnglishPost.org, a blog whose mission is to share lessons for those who want to learn and improve their English