Lean Thinking

Tuesday, 25 March 2014 00:00

Estimation Part 2 - Accuracy vs Precision

Published in Agile

Last time we looked at why we estimate and why there is always pressure to make our estimates more accurate. We have come up with a vast number of methods for estimation all of which aim to improve accuracy. The problem is that most of them don't. What they improve is precision instead.

Most people think of accuracy and precision as being the same thing. But they aren't. My nerdy and pedantic engineering background tells me that accuracy is how close to the true value a measurement is, while precision is a measure of how reproducible the measurement is. A more formal definition (thanks to Wikipedia) is -

In the fields of science, engineering, industry, and statistics, the accuracy of a measurement system is the degree of closeness of measurements of a quantity to that quantity's actual (true) value. The precision of a measurement system, related to reproducibility and repeatability, is the degree to which repeated measurements under unchanged conditions show the same results.

Monday, 10 March 2014 00:00

Estimation Part 1 - Why Do We Estimate?

Published in Agile

A couple of posts back I mentioned Estimation and my desire to poke a stick at the hornet's nest that estimation can be. Estimation is always a controversial topic. It's often at the heart of serious conflicts within organisations. There are a huge number of estimation methods and techniques but nothing seems to prevent these issues from coming up. Before I poke a stick into the hornet's next (well, not so much poke as take a full bodied swing with run up and follow through), I'll spend a little while looking at why we estimate in the first place.

Any time we have two parties involved in something there is estimation happening. Right back from prehistoric times -

Ogg - I estimate that this stone axe is worth the same as that reed bag filled with nuts so let's trade.

Ugg - I estimate that this reed bag filled with nuts is worth at least 2 axes so let's not.

Ogg - Seriously? You're taking food away from my family... these axes are the finest workmanship. Maybe one axe plus a flint scraper but that’s the best I can do.

And so on.

 

Monday, 11 November 2013 00:00

The Problem With Projects

Published in Agile

They say that when all you have is a hammer, every problem looks like a nail. It’s the same in business – when all you have is a project management methodology, everything looks like a project. Most organisations have become very project focussed. Everything is a project. New release of software – project. Some process change – project. That’s great. Projects are good. They are certainly better than the ad-hoc approach we had before projects. But projects do have some drawbacks.

To work out what the drawbacks are, we need to look at what a project is. A project is defined (by the PMI who should know) as something that has a defined scope, a defined start and a defined end date.  So projects are finite in length. Anything without an end date isn’t a project, it's business as usual.

Calendar

« January 2018 »
Mon Tue Wed Thu Fri Sat Sun
1 2 3 4 5 6 7
8 9 10 11 12 13 14
15 16 17 18 19 20 21
22 23 24 25 26 27 28
29 30 31