There are several possible causes if a calculation field does not have a value:

• The form in which the calculation is located, has not been opened for the participant in question. Please note that you should always open the form in which the participant is located, so that its value can be updated.
• The calculation template might be inaccurate - check your calculation again.
• In SPSS, calculation fields are seen as numeric fields, see troubleshooting SPSS.