Spider Project keeps history and shows trends of any project parameter including total float of any activity and/or project phase that are selected.
You don't need to use Excel or anything else.
We usually look at the speed of contingency reserve consumption (success probability trends) that give more information for project performance analysis.
Best Regards,
Vladimir
Member for
16 years 7 months
Member for16 years7 months
Submitted by Gary Whitehead on Fri, 2013-07-05 09:40
I agree the measure can be very dynamic (which is why I use trend lines to smooth things out).
But I do find an issue with this and any metric that looks at total float, in that if the project completion is delayed then all non-critical paths and activities have their total float increased (I don't use project completion constraints), which can give a false picture suggesting that everything apart from the critical path is doing well. It's something that can be overcome through explanation, but the more times you have to explain / justify a metric then the less useful it is.
As to using planning software to calculate: yes I think you could set up a calculated field to work out your float burn metrics in most major planning software. You could certainly do it in excel. If I get time (and I probably won't, if I'm honest -Busy boy at the moment, and I'm moving house in a fortnight), I'll have a go at doing so for you. -It would be interesting to run both my float erorison and your float burn measures side by side on a project to see how they compare.
For my float erosion chart, I just take a copy of the total float for each path after each update and plug it into an excel table -no additional calcs are required (other than the trendlines, which excel handles)
Cheers,
G
Member for
20 years 7 months
Member for20 years7 months
Submitted by Stephen Devaux on Thu, 2013-07-04 12:55
Hi, Gary. How interesting that we have both been wrestling with the same issue.
I think your float erosion chart is a great idea! As you say, it's got the big advantage of being highly visual. And "trend lines" are great tools for showing where we are headed.
The one thing that I'd say is that I see the data as being very dynamic -- in the example I created, the MFBR changed, due to an ancestor's slippage, before the path ever started. If project completion is delayed, that would simply be another change to incorporate in the data, but in essence it would be no different than if an ancestor slips: in either case, the denominator of the MFBR formula will change, in one case increasing and in the other decreasing.
Unfortunately, I don't know of any PM software that has this functionality, do you? I suppose there may be some way to program a macro that will filter out the durations and float toals of a path and divide it by the elapsed time from earliest early start to the next activity with zero float... but that kind of programming is quite beyond me.
It's an interesting area of investigation, though.
I've been using a somewhat simpler & coarser method to track the same thing:
I plot a "float erosion" chart, with TF of various paths through the project on the y axis, and time from project start to project completion on the x axis.
It's fairly insinctive & easy to explain to non-planners that if the trend of a path's float looks like it will cross the y axis (i.e. become critical) before the end of the graph (i.e. the end of the project), then timely project completion is at risk from that path of activities.
It's also a very visual way to highlight the impact on risk of delaying the project from both actual delays and potential decisions which do not impact on the critical path.
One problem I have encountered (and imagine would be similar with your approach) is that if the project completion is delayed, it makes all the other paths suddenly look a lot better in terms of float erosion/burn -Any thoughts?
Member for
20 years 7 monthsWhy am I not surprised that
Why am I not surprised that Spider would have this functionality?
Thanks, Vladimir.
Fraternally in project management,
Steve the Bajan
Member for
24 years 9 monthsGuys,Spider Project keeps
Guys,
Spider Project keeps history and shows trends of any project parameter including total float of any activity and/or project phase that are selected.
You don't need to use Excel or anything else.
We usually look at the speed of contingency reserve consumption (success probability trends) that give more information for project performance analysis.
Best Regards,
Vladimir
Member for
16 years 7 monthsHi Steve,I agree the measure
Hi Steve,
I agree the measure can be very dynamic (which is why I use trend lines to smooth things out).
But I do find an issue with this and any metric that looks at total float, in that if the project completion is delayed then all non-critical paths and activities have their total float increased (I don't use project completion constraints), which can give a false picture suggesting that everything apart from the critical path is doing well. It's something that can be overcome through explanation, but the more times you have to explain / justify a metric then the less useful it is.
As to using planning software to calculate: yes I think you could set up a calculated field to work out your float burn metrics in most major planning software. You could certainly do it in excel. If I get time (and I probably won't, if I'm honest -Busy boy at the moment, and I'm moving house in a fortnight), I'll have a go at doing so for you. -It would be interesting to run both my float erorison and your float burn measures side by side on a project to see how they compare.
For my float erosion chart, I just take a copy of the total float for each path after each update and plug it into an excel table -no additional calcs are required (other than the trendlines, which excel handles)
Cheers,
G
Member for
20 years 7 monthsHi, Gary. How interesting
Hi, Gary. How interesting that we have both been wrestling with the same issue.
I think your float erosion chart is a great idea! As you say, it's got the big advantage of being highly visual. And "trend lines" are great tools for showing where we are headed.
The one thing that I'd say is that I see the data as being very dynamic -- in the example I created, the MFBR changed, due to an ancestor's slippage, before the path ever started. If project completion is delayed, that would simply be another change to incorporate in the data, but in essence it would be no different than if an ancestor slips: in either case, the denominator of the MFBR formula will change, in one case increasing and in the other decreasing.
Unfortunately, I don't know of any PM software that has this functionality, do you? I suppose there may be some way to program a macro that will filter out the durations and float toals of a path and divide it by the elapsed time from earliest early start to the next activity with zero float... but that kind of programming is quite beyond me.
It's an interesting area of investigation, though.
Fraternally in project management,
Steve the Bajan
Member for
19 years 10 monthsHi BothI am pleased to say
Hi Both
I am pleased to say that I have no idea what you are both jabbering on about.
Best regards
Mike Testro
Member for
16 years 7 monthsHi Steve, I've been using a
Hi Steve,
I've been using a somewhat simpler & coarser method to track the same thing:
I plot a "float erosion" chart, with TF of various paths through the project on the y axis, and time from project start to project completion on the x axis.
It's fairly insinctive & easy to explain to non-planners that if the trend of a path's float looks like it will cross the y axis (i.e. become critical) before the end of the graph (i.e. the end of the project), then timely project completion is at risk from that path of activities.
It's also a very visual way to highlight the impact on risk of delaying the project from both actual delays and potential decisions which do not impact on the critical path.
One problem I have encountered (and imagine would be similar with your approach) is that if the project completion is delayed, it makes all the other paths suddenly look a lot better in terms of float erosion/burn -Any thoughts?
Cheers,
G