You may recall from the introduction to this series that constructive criticism offers positive recommendations for the future. This has implications for the timing of offering criticism. Criticizing an event in progress is often futile, both because it’s frequently difficult to stop or redirect a process in motion and because ongoing events will distract from your message. If the recipient of your criticism is busy, you’re not going to be heard. Wait for a better time.
As with any feedback, the sooner after the behavior criticism is offered, the more effective the criticism is likely to be. One caveat, of course, is that the aftereffects of an ongoing event can be as distracting as the event itself, which has to be balanced against the the preference for delivering your message promptly.
Once the window of effective feedback narrows, additional criticism may be viewed as irrelevant, because the person receiving the criticism has already evaluated the event or behavior and drawn their own conclusions from it or because they have forgotten the details that make your criticism relevant. The greater the delay, the more likely criticism is to be viewed as blame, or even a grudge, since the behavior will appear to be maintaining a disproportionate degree of significance for the person offering criticism when compared the recipient.
Nor is there any good reason to stretch that window. Either the behavior in question will be repeated, offering a better opportunity to offer the criticism, or it won’t, meaning constructive criticism–criticism intended to effect a change–isn’t necessary.
In short, pick your timing wisely. Too soon or too late can hurt your message, but waiting when your timing isn’t ideal rarely loses you anything.