Implications of the 85/95 Rule of Project Management I

by dj on November 24, 2004

So the first thing a project manager should do is go to the owner of each task or subtask in a project and ask for that person's opinion on the probability of success or failure in the time allotted. They will give you a percentage or say "I don't know."

And for heaven's sake, you are asking them their opinion, not telling them your expectations. Cripes, don't queer the data collection just yet, you moron. Ask them what needs to be done to up the percentage of success. Don't expect good answers.

Next day, or next week if you have the time, go around and ask them again the same questions. For people who still say, I don't know, negotiate politely a WAG (Wild-Ass-Guess) out of them. Expect the WAG to be somewhere between 50%-75%. Carefully take note of the conditions that have been stated by the stakeholders. Always assure them that you are not going to hold them to their predictions and beat them over the head if things start going south.

Tally up the numbers. You should have anywhere from 3 to 10 tasks with percentages ranging from 49% to 99% . Going deep (having a lot of tasks) is good because it shows you've done a lot of research & talked to a lot of people. Now you should have two numbers: the expected success percentage of the project without conditions and the success percentage with conditions.

The delta of these two number is important too. I've list a chart below with sample success percentages and what this means:

Example #1

Success without conditions: 95%

Success with conditions: 99%

Delta is 4.

This is a great project to undertake if you are lazy and don't want to get fired. Basically, it's going to be a success even if you only show up at the office for 2 hours of the day. The downside is that it's probably going to be a boring ride. But boring is good when the economy is bad or you just finished a project from hell and need some down time.

Example #2

Success without conditions: 50%

Success with conditions: 90%

Delta is 40.

You will work hard on this project but your efforts with be appreciated by members of your team. This is a good project to take especially if Those Above You are willing to award Glory Points for success. The downside of this project is that if some of people who quoted the percentages were wildly optimistic, you could get hosed. The bigger the Delta, the more you have to scrutinise the predictions.

Example #3

Success without conditions: 35%

Success with conditions: 75%

Delta is 40.

Even though the percentage of success has only dropped by 15 points, you should run away very fast from projects like this. Remember that people's perception of project success are fundamentally flawed (too optimistic). So you're going to work very hard on this project, people are going to expect success, but you have a very signficant risk of failure. ANY project that has a success with conditions percentage of 60% to 75% should be avoided, but the absolute worst are the ones with a big delta, which means you need to bust your rear end and still end getting zero glory points.

Example #4

Success without conditions: 15-25%

Success with conditions: 49%

Delta is 14-34.

These types of projects are common in R & D. As the success rate drops below 50%, so do people's expectations. These projects are attempted because success means a big payoff. Or at least it should. If you are project managing one of these suckers, you are either a) Entitled to some serious bon-bons like a bonus or promotion if you pull it off or b) having a lot of fun because of the nature of the work. If the answer is c) Neither then I recommend digging out some resume templates when you have a minute.

In conclusion, and it bears repeating over and over, you want to be high (85+) or low (under 50). Getting stuck in the mushy middle happens every once in awhile but if it happens continually then there's a problem with your organization or maybe you.

Watch the Delta too, you should try to alternate between high and low Delta projects or else you run the risk of burning out.

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