Description of column-types used to define covariates

COV: continuous covariate

It is possible to have in a data set one or several columns with column-type COV. There must be one covariate defined per subject-occasion else wise. String “.” can be used to prevent multiple definitions of a covariate for a subject-occasion as it is interpreted as an absence of definition. Therefore, we encourage the user to either define the covariate at each line, or, more simply, at the first use of a subject for readability reasons (even if the covariate has not necessarily to be defined at first occurrence of subject-occasion in the data set).

Format restrictions (an exception will be thrown otherwise):

  • Continuous covariate columns shall contain either strings that can be converted to double or “.”.
  • The covariate must be defined at least each time per subject-occasion.
  • The covariate must remain the same for all the lines within the same subject-occasion.

CAT: categorical covariate

It is possible to have in a data set one or several columns with column-type CAT. It is possible to enter in a CAT column any string and “.” has no special meaning. We strongly recommend to use only alphanumeric characters and the underscore “_” character in the strings of the CAT columns. In the MonolixSuite 2016R1, special characters such as spaces ” “, stars “*”, parentheses “(“, brackets “[“, dashes “-“, dots “.” and slashes “/” are not supported (this feature will be back in the next release).

Moreover, on the contrary to the continuous covariable, the following data set will generate an error

ID OCC CAT
Tom 1 M
Tom 1 .

Format restrictions (an exception will be thrown otherwise):

  • The categorical covariable must be the same for all the lines with the same subject-occasion.