alternatives to agile estimation - a team perspective

ALTERNATIVES to AGILE

ESTIMATION

NEIL KILLICKneilkillick.com

neil_killick #NoEstimates

AND WHEN

WHAT WILL I GET

ESTIMATING OR GUESSING?

MAKING PREDICTIONS <> PREDICTABILITY

USE *REAL* CONSTRAINTS

KEEP TEAMS TOGETHER

USE XP PRACTICES

● Continuous integration

● TDD/BDD

● Pair programming

● Clean code

DELIVER EARLY & OFTEN

FOCUS ON FLOW

ITERATE *AND* INCREMENT

BACKLOG = OPTIONS

● You will NOT build the whole backlog● Knowing this is empowering

DOES SIZE MATTER?

8Smaller, cheaper (?) awesome feature

Awesome feature

13

FOCUS ON VALUE, NOT COST

● Iterative Funding● Emergent Value

USE A SLICING HEURISTIC

● Explicit policy forbreaking up work,e.g. "A story must have only oneacceptance test"

● Slice stories JIT (e.g. in Sprint Planning)● Can add to "Definition of Ready"

WHY IS THIS BETTER THAN ESTIMATING?

● Explicitly promotes the good practice of splitting work to be done

● Avoids cognitive biases

● Easy to measure effectiveness (e.g. mean & median cycle time within x%)

LITTLE'S LAW IS KEY

CYCLE TIME =WIP /

THROUGHPUT

● Size of premises● No. & size of ovens

CONSTRAINTS REDUCE VARIABILITY AND LIMIT WIP

● No. of chefs & drivers● Delivery radius

● Avg. wait time (hours) =Number of orders in progress (WIP)/ Avg. orders completed in an hour (throughput)

● Assume throughput is 50● Using Little's Law, 0.5 = x / 50● x = 25● We should only take on 25

orders at a time

MAX. 30 MINUTEWAIT FOR CUSTOMERS

WHAT IF WE TAKEON MORE ORDERS?

TAKING ON MORE ORDERS MAY INCREASE WAIT TIME

● Now our WIP is 30 orders● x = 30 / 50● x = 0.6 hours = 36 minutes

● If we can actually deliver60 pizzas per hour, waittime will not increase

LIMIT WIP, LOW CYCLE TIME

WIP limits

CYCLE TIME DISTRIBUTION

● Measure actual cycle time to identify outliers

● Measure mean and median averages

EASY TO MEASURE & SHOW

● Update cycle time at daily standup

● Use coloureddots to representnumber of days

An awesome feature that's taken 4 days

IN SUMMARY

● Real constraints breed creativity● Keep teams together● Use XP practices for technical excellence● Put the "iterate" back into iterations!

IN SUMMARY

● Treat the backlog as options● Focus on value, not cost● Slice work using a heuristic● Limit WIP and measure cycle times

Thank you

NEIL KILLICKneilkillick.com

neil_killick #NoEstimates