Can Irrelevant Quantity Information Influence Judgments of Productivity?

By Brad Bell

Imagine that you are working at your desk and you have a pile of papers and books on your desk.  You glance at this pile and think to yourself that you have been quite productive today.  Your judgment is based on the size of the pile on your desk.  While this approach to judging productivity could be a valid indicator of productivity in some situations, it may often not be.

In their first experiment, Josephs, Giesler, and Silvera (1994) had participant complete a task in which they had to put a slash mark through every letter c that they saw in paragraphs.  All participants were stopped after completing five paragraphs.  Participants put their completed work in an outbox.  In one condition, pages were attached to journals (journal condition).  In the other condition, the pages were not attached to journals (page condition).  On the average, participants in the journal condition rated their own productivity as higher than participants in the page condition. (1)  

Their first study demonstrated that an irrelevant quantity factor (pile size in an outbox) could influence judgments of their own productivity.  In their fifth experiment, Josephs et al. (1994) demonstrated that this irrelevant quantity factor (pile size in an outbox) influence judgments of their own productivity only when it was in full view when they made their productivity judgments.

There are important practical implications.  When judging our own productivity at work it may be best to make these judgments when an irrelevant quantity factor (e.g., pile size in an outbox) is not in our view.    Irrelevant information may influence the judgments of writers and publishers.  Writers may write books that are longer than they need to be.  They may add unnecessary words to make the books longer.  This could result in too much paper being used and readers being unhappy with the time and effort it makes to read something.  Moreover, publishers may reject worthy books because they do not contain enough words.


1.  See their article for other findings.


Josephs, R. A., Giesler, R. B., & Silvera, D. H.  (1994).  Judgment by Quantity. Jourmal of Experimental Psychology: General, 123, 21-32.