Live Chat ×
Skip to main content

(PS-1739) Reviewing Means of Calculating Schedule Updates with Out-of-Sequence Progress

Primary Author: Dr. Fredric L. Plotnick PE

Audience Focus: Advanced
Application Type: Application
Venue: 2014 AACE International Annual Meeting, New Orleans, LA, USA

Abstract: The alternate algorithms of retained logic and progress override were developed to be utilized on the original ADM (arrow diagramming method) format for CPM. It was understood by initial developers that neither choice was correct but merely set options to be overly pessimistic or optimistic. Improvements in computers enabling solution of PDM (precedence diagramming method) logic networks implemented only these choices without regard to other aspects of the PDM format.

A solution avoiding either bias is posited in this paper, and is called by the author a Modified Out-of-Sequence Algorithm. While both retained logic and progress override algorithms involve use of the traditional finish-to-start form of restraint, the modified out-of-sequence algorithm also utilizes a finish-to-finish form of restraint. The protocol was first suggested by the author in 2004 and published in 2005 (and 2010) in CPM in Construction Management, 6th and 7th editions.