Redmine

In the section on issues, when I check for a issue, the application allows the output data is displayed, for example, the following columns (Project, author, start date, estimated time, ...),but if I compare the “estimated time” to the “spent time”, I can not do because the “spent time” field can not be selected, in the options.

Is there any way of contrast, by issue, the “estimated time” and the “spent time”?

Thank you very much.