A few weeks ago, we published some of the ways logical inconsistencies can be built into network logic (see the post here /2022/05/18/cpm-scheduling-the-logical-way-to-error-1/). This post covers some more of the logic challenges from Section 3.5 of Easy CPM. For the most part, this type of problems will not show up in the automated checking tools applying test such as the DCMA 14 point assessment (see more on the DCMA assessment and schedule quality at: https://mosaicprojects.com.au/PMKI-SCH-020.php#Overview).
The naming convention is borrowed from Miklos Hajdu. In all cases the links shown in the diagram are the controlling links, in a ‘live’ schedule there are likely to be many other links as well.
Increasing Normal Decreasing Neutral
An increase in activity B will delay completion, but a reduction has no effect. There are two variations on this type of construct.
A 1-day increase in the duration of activity B will increase the project duration by one day, however, reducing the length of activity B has no effect on the project’s duration.
Increasing Neutral Decreasing Reverse
An increase in activity B has no effect, but a reduction will delay completion. Again, there are two variations on this type of construct.
A 1-day increase in the duration of activity B has no effect on the project’s duration, however, reducing the length of activity B by 1-day will increase the project duration by one day.
Easy CPM, is designed for people who know how to drive scheduling tools and want to lift their skills to the next level. The book is available for preview, purchase (price $35), and immediate download, from:
https://mosaicprojects.com.au/shop-easy-cpm.php
Pat Weaver
Lynda Bourne
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