[whpalmer4]

They are used to convert the internal representation of effort and duration into something a bit more user-friendly. So for example, a task requiring 8 hours of effort will show up as 8 hours instead of 28,800 seconds. Furthermore, longer tasks will be shown as bigger units, so 400 hours of work will show up as something like 10 weeks (assuming the default 8 hours per work day). If you have a work week with differing numbers of hours per day, but a constant number per week, I'd suggest using the average hours per day. It is possible to set inconsistent values for the Effort Conversion Factors, so watch out. 8 hours/day, 20 hours/week, 30 hours/month, 100 hours/year won't get you an error message, but probably will get you misleading results! If you tab from one box to the next, the values will be forced to correspond properly.

The ECF are also used to convert from bigger units to smaller. If you put 5 hours/day in the ECF table, then enter 2d for the effort on a task, 10 hours will be stored as the effort. There is no correlation with the number of hours you might diagram in your custom work week, so you do want to be careful.

Click the boxes in the Durations display for the units you want to see. If you only have hours clicked, everything OP displays will be expressed in hours or decimal fractions thereof. As a rule of thumb, you probably want the smallest unit you would ever assign to a task checked, maybe the next smallest as well.

The ability to have non-standard work weeks is what makes this feature necessary. It gets a bit more confusing when you have weeks and days that aren't all the same length, but if you've got a better solution, I'm sure the Omni crew would be interested in hearing about it. Even though it doesn't take your M8h Tu6h W0h Th10h F4h Sa2h Su14h schedule into account when displaying durations in the schedule (a 16 hour task might be displayed as quite a few different things in that work week depending on when it started), it does do so when assigning the work. A 40 hour task assigned to a resource who works 8 hours per day but has next Friday off will extend an extra day in the schedule to account for that missing day.