Min. 1 and Max. 1 are options that you can select when defining a selection field or an indexed series of mark fields on a form definition. These options specify how many fields respondents are supposed to fill in. You can find Min. 1 and Max. 1 on the Standard tab of the Field dialog.
Select Min. 1 to indicate that the series must contain at least one filled-in field.
Select Max. 1 to indicate that only one mark field in the series can be filled in.
When you select Max. 1, Transfer single value (sum) is automatically selected, as well. You cannot deselect it. If Transfer single value (sum) does not suit your purposes, specify 1 in the Max. no. of marks box on the Options tab instead of selecting Max. 1.
You can also select both options.
Any time you specify how many fields are to be filled in, discrepancies between what you specify and the actual number of filled-in fields must be resolved during validation or verification. The most efficient way to do this is to also select options for resolution. What happens by default is that a validation error occurs.
Instead of selecting Min. 1 or Max. 1, on the Options tab you can specify another number of filled-in fields to be the minimum and/or maximum allowed.
Specification of mark fields and selection fields
For more information and choices on how FORMS handles and assigns values to selection fields and series of mark fields, see Options for mark fields and selection fields.