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Slides as given for the Feb. 12, 2014 talk at Bay Area Software Testers. (btw, I failed to give credit for the "Stand Back!" t-shirt image, it was from the XKCD T-shirt here: http://store-xkcd-com.myshopify.com/products/try-science) Also forgot reference to the paper on Fibonacci numbers in planning poker affecting estimates: http://simula.no/publications/Simula.simula.1282/simula_pdf_file
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fix youestimatingbad habitsTED M. YOUNG
RENAISSANCE CODER & AGILE/LEAN HERETIC
AT GUIDEWIRE SOFTWARE
estimating bugsAND OTHER "OVERHEAD"
ignoring all previousor other projectsREFERENCE CLASS FORECASTING (OUTSIDE VIEW)
LARGE ORGS HAVE AN ADVANTAGE HERE
The prevalent tendency to underweight, or ignore, distributional information is perhaps the major error of intuitive prediction.
TVERSKY & KAHNEMAN, 1977
ignoring variabilityof velocityVELOCITY CAN EXHIBIT A ± 2× SPREAD OF VARIATION
Bad habit number 8
not using statistics
STATISTICS
From: Troy Magennis 2012
using single valuesNEGLECTING DISTRIBUTIONAL INFORMATION
WHAT WE THINK OUR ESTIMATE DISTRIBUTION IS
Image from "Estimates in Software Development", Dubakov 2013
flaw of averagesWHY EVERYTHING IS BEHIND SCHEDULE
ESTIMATE DISTRIBUTION IS MORE LIKE LOG-NORMAL OR WEIBULL
ATTRIBUTE SUBSTITUTION?Image from "Estimates in Software Development", Dubakov 2013
treating every type of estimate the same wayEPICS, THEMES, STORIES, TASKS: POINTS FOR ALL!
Bad habit number 3
ignoring value ofthing being estimatedSPEND LOTS OF TIME ON THINGS OF LITTLE VALUE
CUZ IT'S EASIER!
Bad habit number
think about your estimate not theirsYOU UNDERESTIMATE YOUR OWN COMPLETION TIME
BUT NOT OTHERS'!
Bad habit number
estimatingthings you'llnever work on
Bad habit number 5
only estimatingtouch timeDISCUSSION? COORDINATION? BAH, WHO NEEDS IT?
Bad habit number 3
estimating timeinstead ofcomplexity or effortPOINTS/SIZES GET EQUATED TO TIME
IN BOTH DIRECTIONS!
Bad habit number 9
completion dateorhours of work?THEY'RE NOT THE SAME THING
using non-linearvalues for estimatingFIBONACCI AND NON-LINEAR SEQUENCES DECREASE ESTIMATES
USE T-SHIRT SIZES INSTEAD
using planning pokerATTEMPT TO REMOVE ANCHORING BIAS
REPLACES IT WITH SOCIAL ANXIETY
estimating what we think the story isINSTEAD OF WHAT IT ACTUALLY IS
WHAT WILL BE DIFFERENT IF THIS STORY IS IMPLEMENTED?
premature estimationHAVE YOU EXPLORED THE OPTIONS BEFORE COMMITTING?
treating all estimatesas commitmentsNOT APPROPRIATE
UNTIL WE GET BETTER AT ESTIMATING
practicing estimationwithout deliberatenessPRACTICE ≠ DELIBERATE PRACTICE
REF. DEFINITION OF INSANITY
not experimentingIF ESTIMATING DOESN'T DO EVERYTHING YOU NEED
HOW ARE YOU TRYING TO IMPROVE?
overvaluingestimationSTOP FIGHTING OVER PRECISION
YOUR ACCURACY DOESN'T MATTER EITHER
deliberate deceptionTHE MACHIAVELLI FACTOR OR OVERLY SUBSERVIENT
BOWING TO POLITICAL PRESSURE
assuming youneed estimatesMAYBE YOU DON'T?
HOW WOULD YOU FIND OUT?
#NOESTIMATES
Bad habit number 1
Final Questions?TWITTER - @JITTERTED EMAIL - [email protected]
HTTP://ABOUT.ME/TEDMYOUNG
Resources 50 Quick Ideas to Improve Your User Stories (In-progress Leanpub e-book)
◦ http://leanpub.com/50quickideas
Throughput (Blog entry by Zsolt Fabók)◦ http://zsoltfabok.com/blog/2014/01/throughput/
Intuitive Prediction (1977 paper by Kahneman & Tversky about the "planning fallacy")◦ http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA047747
Judgment under uncertainty (1974 paper by Tversky & Kahneman)◦ http://www.sciencemag.org/content/185/4157/1124.short
Delusions of Success: How Optimism Undermines Executives' Decisions (Lovallo & Kahneman)◦ http://j.mp/delusions-of-success
Modeling, Simulation & data mining (Slides from Troy Magennis & Larry Maccherone)◦ http://j.mp/simulation-magennis
Estimates in Software Development (Dubakov, May 2013)◦ http://www.targetprocess.com/articles/estimates-software-development.html