1). Conceptualize your analytical model. Facets is based on an additive model:

 

observation = person ability - item difficulty - rater severity - time-point-challenge - .......

 

What is your additive model?

 

2). "Dummy facets" which aren't part of the additive model, but are required in order to investigate fit and interactions, such as, "rater gender".

 

Do you have any dummy facets? These will be anchored at 0 logits in the analysis, so that they don't alter the additive model.

 

3). Number all the facets:

 

1. Persons

2. Items

3. Raters

4. Time-points

5. .....

 

6). Within each facet, there is a list of elements:

Persons: Fred, George, Mary, ...

Items: ...

Raters: ...

 

7). Construct the Excel spreadsheet with one column for each facet and one column for the observation.

One facet can have range, such as 1-4, so that there are 4 columns of observations.

 

8). Construct the Labels= list of facets and elements.

 

9). Put in anchor values of 0 for the elements of the dummy facet.

 

10). Write the Models= specifications that match your analysis.

 

11). Complete the Facets specifications.

 

12). Run the analysis.