What Are Merge Hotspots And How To Find Them

Activities with a disproportionate number of predecessors or successors suggest potential pinch points or merge hotspots. Merge hotspots can indicate an increased probability of delay due to the compound effect of all preceding or succeeding logic. To put it another way, an activity with many predecessors is likely to suffer delay due to the increased probability that at least one predecessor is in turn delayed. Similarly, an activity that has multiple successors will have a disproportionate impact upon the overall schedule if it itself is impacted by delay. The compound effect of a schedule with many merge hotspots can also indicate a reduced likelihood of successful delivery on time.

In this video, we will use the Dashboard Creator to generate a report, from which we can determine and review the merge hotspots within a schedule. From the Dashboard menu, click Current Dashboard. Click to add a new chart, and then select Schedule Density. For this example, we will look at the activity succeeding logic, but the process is the same for predecessor logic. Drag with your mouse to resize the chart if needed.

As we can see here, the majority of the tasks in this schedule have three or less succeeding tasks. However, there are a significant number of tasks that have four or more successors, which may be a cause for concern. To dive deeper, we can export the chart as a Microsoft Excel sheet by opening the menu and clicking Export chart data. The toolkit will now generate and download an Excel report.

In addition to a summary of successors per task, the generated workbook also provides a full logic list. Project tasks are highlighted in blue, and their respective successors are listed underneath with link type and lag duration. The workbook also divides activities into separate worksheets depending on the number of successors they have. For example, we can see that there are two tasks with 10 successors. If we open the respective worksheet, we’ll be able to see the linked activities.

We now know that if the drainage WPP sign-off or review of survey information is delayed, 10 activities will also be delayed, leading to a knock-on effect and massively hindering the project’s progress. The XER Toolkit enables you to identify merge hotspots, so you can prepare and stay in control of your project’s schedule.