This dialog allows you to specify the precision with which measured values were rounded. As an example, suppose that you have income data, with incomes rounded to the nearest $1000. You would enter "1000" in the dialog box as follows.
Then, say, an income that was recorded as $97000 would be treated as between $96500 and $97500. In other words, "97000" would be be recoded as "96500<<97500".