ID numbers and phone numbers are nominal data rather than interval data (i.e. you cannot do calculation with ID numbers) Can I still use a number field instead of a text field to carry nominal data?
Yes and no.
Do not use a number field for ID numbers. If the ID number starts with a "zero" such as "0165," the number field will truncate the "zero" and store it as "165."
Do use a number field to indicate group membership or flag. For example, you can use the values "member" and "non-member" for a text field named "member," and the values "complete" and "incomplete" for a flag such as "completed assignment 1?" However, using text data for these fields have two shortcomings:
- It is harder to summarize the text-based data. On the other hand, if I use "1" and "0" instead, I can sum the total to find out the frequency count of members or the number of people who completed the assignment.
- When the text-based data for membership or flag are displayed in a table, it is difficult for me to see the big picture. Please compare the following two tables. Which one is easier to look at?