MS Project assumes that you are loading a “closest to the pin” estimate for task duration. fn That means the duration has a 50% chance of coming in ahead of schedule and a 50% chance of finishing late. There’s a twist to this game that many project managers fail to recognize: Very few people give you a 50/50 estimate when you ask for a task duration. Unless you train the estimators each person will give you their personal estimate based on his/her risk tolerance. It might be a 90% estimate from Ms. Risk Averse and a 30% estimate from Mr. Everything’s Easy.
Tip: Take the time to teach and convince everybody on your team to provide a consistent 50/50 estimate.
Now that everybody has given you their closest to the pin estimate, what is the probability of the final schedule date? That’s right, 50% … you paid attention in 5th grade math!
For some executives, that’s like saying that your project may or may not hit the delivery date.
Executive: “Are you telling me that your schedule has a coin flip chance of occurrence?”
Me: “Yes, I am!”
Don’t you just hate being the first person to educate the huddled masses? How will they respond? Can you escape the executive review in one piece? To keep your job, what can you / should you do to bound the estimate?
__________
fn. Here’s proof that MSP assumes that you are loading a 50% estimate: your duration is automatically loaded in the “most likely case” column of the PERT table.
