Inter-Rater or Inter-Observer Reliability
Used to assess the degree to which different raters/observers give consistent estimates of the same phenomenon.
Test-Retest Reliability
Used to assess the consistency of a measure from one time to another.
Parallel-Forms Reliability
Used to assess the consistency of the results of two tests constructed in the same way from the same content domain.
Internal Consistency Reliability
Used to assess the consistency of results across items within a test.