Word does not handle negative numbers correctly in calculated fields, because Word apparently makes the comparison between such items as alpha-numeric character groups rather than negative numbers.

Consider the circumstances where you have a database containing temperatures between 10° and -20° and you wish to present information in a mail merge based upon that data. For example, you may wish to recommend the use of a coat when the temperature is below -5° (the figure being chosen to demonstrate the problem rather than a climatic dress recommendation )

Logic would suggest a simple conditional field as shown below:

Running the merge produces the odd results listed below, which are clearly not what is required

One answer is to ensure that calculations are only conducted with positive numbers, to which end the ABS function will come in useful. Thus to modify the previous example, we first separate all the negative items (items less than 0) from the positive items, then deal with each separately, using nested IF fields as shown in the following example.

The first condition produces the result "No coat required" for all positive temperatures (those of 0° or above).

Negative numbers are converted to positive, then further compared to establish whether they are greater than 5. As the numbers are now positive, numbers greater than 5 are the numbers that were formerly below -5°.

Alternatively, you could use the SIGN function to establish whether or not numbers are negative. The effect is the same.

Even simpler you could use the IF function, which can be used to return 1 or 0 and which can be used with a conditional field to produce the required result:

Re-running the merge with any of the above produces the following, now correct, result:

Thanks to fellow Word MVPs Greg Maxey for raising this issue, and Cindy Meister and 'Macropod' for help with the solutions.