The Conners 4 is well-suited for use in monitoring treatment effectiveness. When using the Conners 4 for this purpose, it should be administered at least twice before beginning treatment. These initial administrations help establish a baseline to which subsequent administrations can be compared. The danger in doing only one administration prior to treatment is that a single administration will often produce inflated scores—treatment is usually sought when behavior is at its worst, when behavior impacts daily functioning the most, and/or tolerance or coping levels are at their lowest. A phenomenon known as regression to the mean can result, and this phenomenon may obscure measurement of treatment effectiveness. It will be hard to judge whether the observed improvement occurred due to treatment or because the exasperating situation simply got better.

When evaluating the effectiveness of medication treatment, raters should be asked to consider times of day when the medication is in effect. If ratings are based on times of day when the youth is not on medication, drug effects may have worn off. For example, if medication is taken only during school hours, parents may not notice drug effects if the medicine has worn off by the time the youth arrives home from school.