Chap

Chapter 3:

* Some measures may be norm-referenced while others are criterion-referenced.

* Norm-referenced measures: each test-takers performance is interpreted with reference to a relevant standardisation sample or norm group.

* Criterion-referenced measures: compare the test-takers performance to the attainment of a defined skill or content.

* The standard normal distribution

* The normal distribution is the standard normal distribution which is bell-shaped and has a mean of 0 and a standard deviation of 1.

* Raw scores obtained by test-takers on psychological measures have little or no meaning. In order to make the interpretation more meaningful, these raw scores are converted to normal(standardised) scored through statistical transformation.

* A norm can therefore be defined a norm is a measurement against which an individual’s raw score is evaluated so that the individuals position relative to that of the normative samples can be determined.

* The procedure for establishing such normative samples or norm groups is of crucial importance in any selection procedure.

* Establishing norm groups

* Norm groups have 2 subgroups:

1. The applicant pool

2. Incumbent population

* The choice of such a norm group has to be representative of both the applicant pool and incumbent population as well as appropriate for the position the assessment is conducted for.

* The similarities between the norm group on the one hand and applicant and the incumbent groups on the other hand are established by means of comparative aspects such as ethnicity, gender, age and educational background.

* Co-norming of measures

* Often happens that an assessment practitioner wants to compare scores obtained on different, but related measures, in order to test for possible learning or memory effects.

* Co-norming entails the process where two or more related, but different measures are administered and standardised as a unit on the same norm...