Gantt chart with resource de-confliction

Question

I like to use Gantt charts to model the time tasks will take and the dependencies of those tasks. For reference, I use GanttProject but I am not tied to it.

One issue I've had, however, is handling who is doing what task and avoiding any individual from being over-tasked.

For example, lets assume I have a 1 person project and have two tasks:

1. Design logo.

   • Duration: 5 days @ 100% time
   • Assignee: Bob

2. Write code

   • Duration: 3 days @ 100% time
   • Assignee: Bob

Now, neither of these tasks have dependencies on each other. The order does not matter. However I want to make sure Bob is never assigned to work more or less than 100% time.

The solution I'd like a Gantt project to provide is to automatically balance Bob's time by one of the following:

1. Automatically schedule task 1 and 2 to be twice as long and at 50% time.
2. Automatically make Task 1 and Task 2 sequential so Bob does one and then the other.

Does anyone know if there is any Gantt software that could automatically handle over-work issues like this?

Answer 1

You have described a very simple version of the the classic resource-constrained scheduling problem. The mainstream project scheduling tools (e.g. MS Project, Oracle Primavera P6, Elecosoft PowerProject, Spider Project) all address the problem by: a) first scheduling the project using standard logic-based precedence, i.e. the critical path method (CPM) and its derivatives; then b) applying heuristics to delay lower-priority tasks from their CPM dates as needed to relieve overallocations. Optimized solutions are extremely difficult to obtain in general, so "good enough" is the typical objective, and some user tweeking of the leveling rules is normal. The different tools provide different levels of sophistication here.

For your simple example, these resource levelers would apply a solution similar to your approach number 2, forcing the two tasks to be sequential. Your approach number 1 - stretching and overlapping the two tasks - can be done manually in the software that I'm most familiar with, but the resulting multi-tasking of resources would normally be frowned on. Asking Bob to continuously alternate his attention between Task A and Task B is inefficient, especially if they are not related tasks.