Using a new technique, Hemoglobin was estimated in a blood sample. The test was repeated for 10 times. The reports were 9.5, 9.2, 9.4, 9.6, 9.7, 9.9, 10.5, 12.1. Accurate v. ue of Hb was estimated by standard test to be 10.2. The new technique has:

Reliability is synonymous with consistency of test, i.e. it should produce consistent results when repeated n number of times. Validity refers to the degree in which our test or other measuring device is truly measuring what we intended it to measure, i.e. accuracy of the test. The validity often is associated by comparing a measurement method with the best possible method of measure that is available. For example, the validity of BP measurements obtained by a sphygmomanometer might be compared with those obtained by intra-arterial measurements.