<story><title>The unfortunate math behind consulting companies</title><url>http://blog.asmartbear.com/consulting-company-accounting.html</url></story><parent_chain></parent_chain><comment><author>pdx</author><text>While I agree with the general &quot;consulting is not the path to riches&quot; tone of the article, I have a small nit.&lt;p&gt;What the author is doing is adding up all the worst case scenarios into one big ugly pile of bad.&lt;p&gt;It reminded me of an mp3 player I designed once.  I had to allocate z-height for the LCD.  An LCD can have a lot of subcomponents (EL Backlight, FPC cable, rear reflective film, glass, front polarizing film, plastic protective lens, etc.  All of these have min/max dimensions on the spec sheet.  An inexperienced engineer, such as I was, would just add all the max dimensions to get max z-height of the LCD and design for that.  But I also needed it not to rattle around, so I needed my design to also work if all the dimensions came in at their minimum.  Woops!  It&apos;s thickness could apparently vary wildly.  I didn&apos;t want to burden my product with the complexity it would take to handle so much variance in one component.&lt;p&gt;I then learned that tolerances are never added up &quot;worst case&quot; or you&apos;d never get anything built.  Instead, you do a root mean square of them.  The chances of every component in your subassembly coming in at it&apos;s absolute maximum are minuscule.  The root mean square method accounts for this.&lt;p&gt;Anyway, I felt that the author of this piece was doing a little max tolerance stacking.</text></comment>
<story><title>The unfortunate math behind consulting companies</title><url>http://blog.asmartbear.com/consulting-company-accounting.html</url></story><parent_chain></parent_chain><comment><author>raganwald</author><text>I long time ago I was playing bridge with a genius named Arno Hobart. I asked him what he was up to, and he told me he was in the vending machine business. &quot;Oh?&quot; I asked, surprised that such an intelligent man would work with such mundane products.&lt;p&gt;&quot;One of the things I like about this business,&quot; he explained, &quot;Is that I make money while I sleep.&quot; Yes, he really is smarter than the average bear.</text></comment>