<p>I come from a fairly strong OO background, the benefits of OOD &amp; OOP are second nature to me, but recently I've found myself in a development shop tied to a procedural programming habits. The implementation language has some OOP features, they are not used in optimal ways. </p>

<p>Update: everyone seems to have an opinion about this topic, as do I, but the question was:</p>

<p><strong>Have there been any good comparative studies contrasting the cost of software development using procedural programming languages versus Object Oriented languages?</strong></p>

<p>Some commenters have pointed out the dubious nature of trying to compare apples to oranges, and I agree that it would be very difficult to accurately measure, however not entirely impossible perhaps. </p>

Good idea.  A head-to-head comparison.  Write application X in a procedural style, and in an OO style and measure something.  Cost to develop.  Return on Investment.
What does it mean to write the same application in two styles?  It would be a different application, wouldn't it?  The procedural people would balk that the OO folks were cheating when they used inheritance or messaging or encapsulation.
There can't be such a comparison.  There's no basis for comparing two "versions" of an application.  It's like asking if apples or oranges are more cost-effective at being fruit.
Having said that, you have to focus on things other folks can actually see.
Time to build something that works.
Rate of bugs and problems.
If your approach is better, you'll be successful, and people will want to know why.
When you explain that OO leads to your success... well... you've won the argument.