You can change the reference event for the response and the reference level for any factor. Changing the reference event or level does not affect the overall significance, but it can make the results more meaningful. For more information, go to Interpreting the estimated coefficients in nominal logistic regression.

- Reference event
- Enter the reference event if you want to change the default event for the response variable. (Text and date/time levels must be enclosed in quotation marks.) By default, Minitab sets the following reference events based on the data type:
- For numeric variables, the reference event is the largest numeric value.
- For date/time variables, the reference event is the most recent date/time.
- For text variables, the reference event is the last in alphabetical order.

- Reference level (enter categorical predictor followed by level)
- Enter the categorical predictor followed by the reference level if you want to change the default level. (Text and date/time levels must be enclosed in quotation marks.) By default, Minitab sets the following reference levels based on the data type:
- For numeric predictors, the reference level is the lowest numeric value.
- For date/time predictors, the reference level is the earliest date/time.
- For text factors, the reference level is first in alphabetical order.

If you have defined a value order for a text variable, the default rules do not apply. For the reference event for the response, Minitab designates the first value in the defined order as the reference. For a categorical predictor, Minitab designates the last value in the defined order as the reference event. For more information, go to Change the display order of text values in Minitab output.

You can enter values for estimated coefficients for several scenarios. For example, you may want to provide starting estimates so that the algorithm converges to a solution, or you may want to validate a model with an independent sample. For more information, go to Entering initial values for estimated coefficients.

- Starting estimates for algorithm
- Enter the column containing the initial values for model parameters. Specify initial values for model parameters or parameter estimates for a validation model.
- Estimates for validation model
- Enter the column containing the estimated model parameters. Minitab will then fit the validation model.

In Maximum number of iterations, enter the maximum number of iterations that Minitab performs to reach convergence. The default value is 20. Minitab's logistic regression commands obtain maximum likelihood estimates through an iterative process. If Minitab reaches the maximum number of iterations before convergence, the command terminates.