## Model Specification for Repeated Measures Models

Model specification for a repeated measures model is a character vector or string scalar representing a formula in the form

`'y1-yk ~ terms'`,

where the responses and terms are in Wilkinson notation.

For example, if you have five repeated measures y1, y2, y3, y4, and y5, and you include the terms X1, X2, X3, X4, and X3:X4 in your linear model, then you can specify `modelspec` as follows:

`'y1-y5 ~ X1 + X2 + X3*X4'`.

### Wilkinson Notation

Wilkinson notation describes the factors present in models. It does not describe the multipliers (coefficients) of those factors.

Use these rules to specify the responses in `modelspec`.

Wilkinson NotationDescription
`Y1,Y2,Y3`Specific list of variables
`Y1-Y5`All table variables from `Y1` through `Y5`

The following rules are for specifying terms in `modelspec`.

Wilkinson NotationFactors in Standard Notation
`1`Constant (intercept) term
`X^k`, where `k` is a positive integer`X`, `X2`, ..., `Xk`
`X1 + X2``X1`, `X2`
`X1*X2``X1`, `X2`, `X1*X2`
`X1:X2``X1*X2` only
`-X2`Do not include `X2`
`X1*X2 + X3``X1`, `X2`, `X3`, `X1*X2`
`X1 + X2 + X3 + X1:X2``X1`, `X2`, `X3`, `X1*X2`
`X1*X2*X3 - X1:X2:X3``X1`, `X2`, `X3`, `X1*X2`, `X1*X3`, `X2*X3`
`X1*(X2 + X3)``X1`, `X2`, `X3`, `X1*X2`, `X1*X3`

Statistics and Machine Learning Toolbox™ notation always includes a constant term unless you explicitly remove the term using `-1`.