The example below illustrates a well-specified operation. The respondent is asked to enter a number and subtract it from a given amount. The operation is indicated by the word ‘minus’ and by the subtraction and equal signs. Lines are provided for the number to be entered and for the resulting number. Both numbers appear in the same column and are adjacent.

A poorly specified operation can be illustrated using the section of the application for the Child Tax Benefit shown below. The respondent is asked to enter ‘world income’ for three years. We will ignore the fact that collecting income amounts for three years will involve some addition. The operation that will be most difficult will be to show this combined income ‘in Canadian dollars.’

No assistance is given to the respondent about how to perform this conversion or where to find the conversion factors. It is also unclear if the money is to be converted into today’s dollars, or reported as dollars at the time the money was made—perhaps a considerable difference. The numbers to be operated upon are not adjacent, the operation to be performed (multiplication) is not indicated in words or by mathematical signs. Despite a ‘definitions’ section on the back of the form (shown on the page following), ‘net amount’ is not described or specified; one assumes it indicates ‘after tax’ income.