Both validity and reliability can be visualized using the
game of darts. If you are unfamiliar with the game, the goal is to throw a little dart
and hit the bulls-eye in the middle of the board. Validity represents the ability to hit
the bullseye accurately on the dartboard; while reliability is how many times you can
hit the same mark on the dartboard in a row. Study the illustrations below and try
to explain each in your own words.

An assessment is reliable if it measures the same thing consistently and reproducibly. If you were to deliver an assessment with high reliability to the same participant on two occasions, you would be very likely to reach the same conclusions about the participant’s knowledge or skills. A test with poor reliability might result in very different scores across the two instances.An unreliable assessment does not measure anything consistently and cannot be used for any trustable measure of competency. It is useful visually to think of a dartboard; in the diagram to the right, darts have landed all over the board—they are not reliably in any one place.In order for an assessment to be reliable, there needs to be a predictable authoring process, effective beta testing of items, trustworthy delivery to all the devices used to give the assessment, good-quality post-assessment reporting and effective analytics.