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Tesler’s Law

Mark Mzyk | August 17, 2008

I was reading Bill de hOra the other day, and he mentions Tesler’s Law. I’d never heard of Tesler or his law, so I followed the link. Turns out Larry Tesler is a pretty big name in the user interface field, as far as I can gather, although his law is lacking a Wikipedia page (perhaps I should fix that).

Tesler’s Law is this:

The Law of Conservation of Complexity: Every application must have an inherent amount of irreducible complexity. The only question is who will have to deal with it.

In the interview Bill de hOra links to, Tesler further enumerates on his law:

If a million users each waste a minute a day dealing with complexity that an engineer could have eliminated in a week by making the software a little more complex, you are penalizing the user to make the engineer’s job easier.

Whose time is more important to the success of your business? For mass market software, unless you have a sustainable monopoly position, the customer’s time has to be more important to you than your own.

I agree. I think if we look at some of the most successful applications in history, we’ll find Tesler’s law at work behind their success.


  1. Pingback from “Smart” applications « Riverside Publishing Next Generation Blog:

    [...] than they need to by taking over some (if not all) of the complexity of a task. In alignment with Tesler’s Law, the system will shift as much of the complexity for a task from the user and to the system as [...]

    September 25, 2009 @ 10:36
  2. Pingback from RESTful Web Services, Part 1/3: Introduction « PolyAwesomeism:

    [...] More responsibility and complexity for API consumers to discover URLs, which makes it slower to harder to adopt — especially if OAuth is involved. Also does not respect Tesler’s Law -1 [...]

    March 19, 2012 @ 07:25
  3. Comment by Linda King:

    This is very interesting, I just happened upon it looking for another Tesler. I never thought about this but I understand and am enlightened. I will use this knowledge the rest of my life and be better for it. Thank you for providing this sight for me to happen to find.
    Sincerely, Linda King

    December 19, 2012 @ 04:10