Model= and

Rating Scale=

Scale codes

Meaning for this model

D

Dichotomous data. Only 0 and 1 are valid.

Dn

Dichotomize the counts. Data values 0 through n-1 are treated as 0. Data values n and above are treated as 1. E.g., "D5" recodes "0" to "4" as 0 and "5" and above as 1.

R

The rating scale (or partial credit) categories are in the range 0 to 9. The actual valid category numbers are those found in the data. RK to maintain unobserved intermediate categories in the category ordering.

Rn

The rating scale (or partial credit) categories are in the range 0 to "n". Data values about "n" are missing data. The actual valid category numbers are those found in the data. If 20 is the largest category number used, then specify "R20".

RnK

Suffix "K" (Keep) maintains unobserved intermediate categories in the category ordering. If K is omitted, the categories are renumbered consecutively to remove the unobserved intermediate numbers

M

Treat all observations matching this model as Missing data, i.e, a way to ignore particular data, effectively deleting these data.

Bn

Binomial (Bernoulli) trials, e.g., "B3" means 3 trials. In the Model= statement, put the number of trials. In the Data= statement, put the number of successes. Use Rating Scale= for anchored discrimination.

B1

1 binomial trial, which is the same as a dichotomy, "D".

B100

Useful for ratings expressed as percentages %.  Use Rating Scale= for anchored discrimination.

P

Poisson counts, with theoretical range of 0 through infinity, though observed counts must be in the range 0 to 255.  Use Rating Scale= for anchored discrimination.

the name of a user-defined scale

A name such as "Opinion". This name must match a name given in a Rating (or partial credit) scale= specification.

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