Many thanks for your response to our article.  Indeed we agree, there are many instances where negative lags are appropriate and the article you provided a link to was certainly an interesting and detailed look at the history and usage of such links. 

To give you a little context that was not very apparent our article, the blog we posted was partly in response to a trend within certain government agencies to actually rule out the use of leads in schedules submitted to them as part of a DOD or DOE program.  And we wanted to underline some of the reasons for this stance.  Indeed we’ve seen language specifically banning their use in some recent government contracts.  This is rather disturbing as it moves these items out of the scheduling guidelines column and places them squarely in the scheduling rules column.  One such contract not only banned the use of Leads, but also banned Lags, and any relationships type other than Finish-to-start.  It was extremely restrictive and hobbled the scheduler’s ability to model certain elements of the project accurately.  Because we work with mostly Primavera P6 in the DOD and DOE contract world, I myself do try to minimize the use of leads simply to avoid blowback.  Ultimately, I believe it behooves the individual scheduler to model the schedule using whatever tools necessary to represent the work most realistically.  If they can defend it rationally, then it’s probably the right kind of link.

Thanks again for your interesting perspective on this somewhat controversial topic.  We appreciate your feedback.