Oh ffs, can we please stop estimating

Olga Loyev

Introduction

Why are we here?

Let’s step back

Estimation

What is it we’re trying to achieve?

What we did

Can we do better?

Work in Progress = # of things in being worked on

Lead Time = Time from start to finish

Throughput= How much you get done per period of time

Looking at our data

The less guessing you do, the better

reporting metrics

Little’s Law:

average WIP = average LT x average TP

http://www.cs.bilkent.edu.tr/~tugrul/CS518/Papers/little.pdfhttp://web.mit.edu/sgraves/www/papers/Little's%20Law-Published.pdf

Conditions/assumptions:

● Items of similar size● Conservation of flow: departure rate =

average arrival rate● All work items that enter the system will

eventually be completed and will exit the system

How do we apply it?Time to complete = N/aTP

Or

Time to complete = N* (aLT/aWIP)

Size of stories?

●

Transition mid project

Risk/issues/considerations?

Time/Price at start of project?- Data

Time/Price at start of project?- NO Data

Forecast future release

Milestones

Final thoughts