Architecture of Tech Interviews

GayleL. McDowell | Founder/ CEO, CareerCup
gayle in/gaylemcdgayle
The Architecture of Interviews
Consistency+ Efficiency+ High Bar + Happiness
June7, 2016 | Talent42

&
candidates are
frustrated confused

gayle in/gaylemcdgayle 3Gayle Laakmann McDowell
They
Don’t
Know…
 Howmany interviews
 Who will be interviewing
 If they’ll code?How?
 What they need to know
 Howdecision gets made
 WHY?
Lotsofmyths
(andmisinformation)!

&
&
companies need
consistency efficiency
high bar happiness

Gayle Laakmann McDowell 5gayle in/gaylemcdgayle
Consistency & Efficiency
Consistency
 Outcome
 Process
 Questions
Efficiency
 Speedy process
 Able to expedite
 Minimal overhead
 Minimal false negatives

High Bar & Happiness
High Bar
 Minimize false positives
 Good, adaptable people
Happiness
 Enjoyable experience
 Makes company look good
 Transparency

7 gayle in/gaylemcdgayle
The Process
Resume Selection
Intro Call w/
Recruiter
Email that outlines
process
Code Assessment
Phone Interview
~4 onsite
interviews
Discussion &
Decision
“Sell” Call / Dinner

gayle in/gaylemcdgayle 8Gayle Laakmann McDowell
Stuff
I’ll
Discuss
 BarRaisersvs. Hiring Committees
 OfflineWork
 Homework vs code assessment tools
 QuestionStyle
 Knowledge, algorithms, pair programming
 Coding Platform
 Real code vs. pseudocode
 Whiteboard vs. computer

Bar Raisers or
Hiring Committees
So different, yet so similar
01

Bar Raisers andHC
Offer transparency
Offer consistency
Keepbar high
Facilitatechange
Can override manager

gayle in/gaylemcdgayleGayle Laakmann McDowell 11
HiringCommittee
Cons
 Overhead
 Delays
 Un-empowering
 Can feel “black box”
 Need good feedback
Pros
 Cross-company consistency
 Keeps barhigh
 Easierto improveprocess

Who’s it good for?
Companies that:
 See5or more devcandidatesperweek
 Wanttoimproveprocess
 Hireforcompany,notteam
 Arenotveryknowledgefocused
Easier to implement early!

HiringCommittee: Best Practices
Meet at least 2x per week
Multiple HCs:
 Beware ofbarcreep /inconsistencies
Let interviewers observe HC
Traininterviewers to write feedback
Quality of decisions rests onfeedback

Bar Raisers
Cons
 Need consistency across
company
 Need to scale team
Pros
 Many ofHC benefits:
 Consistency
 High bar
 Transparency
 But easierto implement
 No bottleneck

Bar Raisers:Best Practices
 Select people who areinherently good
 Experiencedatinterviewing
 Nice, empathetic
 Smart&can challengecandidate
 Train them thoroughly
 Empowerthem
 Assign outside of team
 Watch out for scale/exhaustion!

Offline
Assessments
Homework, code assessment tools,
etc
02

OfflineAssessments
Homework Projects Code Assessment Tools

Homework Projects
Big
Very Practical
Some love this
Lesscheating
 Except:algos
Too immediate
Needs eng time
Disproportionate workload
Scales poorly for candidate

Homework: Best Practices
Show candidate
interestfirst
< 4 hours
 If >4, onsite project review
Architecture, not algorithms
Define review criteria
Avoid confusion with
company work

Homework: Who It’s Good For
Language focused
 Low priority on algorithms / thought process
Experienced candidates (maybe)

Code Assessment Tools
Fast, cheap eval
 Morecandidates
 Non-traditional
Sets expectations for onsite
Consistent data point
Cheating
May turn off senior
candidates

ImplementationOptions
Everyone
Just your “maybe” candidates
Fast-Track

Who It’s GoodFor
Small, mid-sized, and big companies
Value algorithms / problem solving
Lots of candidates
Want to look at non-traditional candidates

Code Assessment: Best Practices
Show candidate interest
first
Beware of cheating
 (But nobiggie!)
Clearexpectations
Pick GREAT questions
 Similar to real interviews
 Unique questions
1 – 2 hour test

Question Style
Pair programming, algorithms,
knowledge
03

What ToAsk
Knowledge
Algorithms
Design/Architecture
Pairprogramming

Knowledge Questions
Good whenyou can’t train skilleasily
Best practice:
 In-depth,ifat all
 Keepita discussion

Algorithm Questions
Smartmatters.
Good for everyone
Best practices:
 Clear expectations with interviewers & candidates
 Ask medium-to-hard & unusual questions

Design/Architecture
Great for experienced candidates
Shows communicationskills
Best practice:
 Prepcandidates.Big unknown!

PairProgramming
 Many candidates enjoy it
 Feels fair & real world
 Assesses codestyle / structure
 Shows interpersonal interaction
 Less understood
 Not greatfor algos
 Interviewer really matters
 Biased by tools

PairProgramming: Best Practices
 Prep/warn candidates
 Need GREAT interviewer
 Give choice of problems
 Okay/good to pick unreasonably big problems
 Guide candidates
 (Okaytoaskquestions,notknowtools,etc.)

Coding Platform
Whiteboard vs. Computers
04

Why We Make Them Code
Can theyput“thoughts”into “actions”?
Do they show good structure and style?
Do they thinkabout theimpact of decisions?

A Game with Secret Rules
… and this is for a
simple problem

Don’t Allow Pseudocode
Unpredictable playing field
Detailsmatter
If “real code” is too hard for them…

How toCode
Big Practical Stuff
Use computer
Pair Programming
Small Stuff
Algorithm-focused
Computer or
whiteboard

Buthow to code?
whiteboard computer

A Case for Computers
 Realistic. Allows tools.
 Candidates feel more comfortable
 (Especially experienced &diversity candidates)
 Faster to write (often)
 Morecode

The Downsideof Computers
Oftenwrite stupid stuff
Desperate attemptfor compilation
Communicationshutsdown
Biased by tools/laptop
“Transition” betweenalgorithm & code

gayle in/gaylemcdgayle 41
z
Gayle Laakmann McDowell
Computer
Best
Practices
Let candidate bring laptop
Instruct: not every detail
Encourage communication and
thinking
Recognize the bias!

A Case for Whiteboards
Encourages thinking & communication
More language agnostic
Consistent across candidates
 Better laptop/tools doesn’t matter
It’s “standard”

The Downsideof Whiteboards
Slow to write
Artificial environment
Can be intimidating

gayle in/gaylemcdgayle 44
z
Gayle Laakmann McDowell
Whiteboard
Best
Practices
Encourage shorthand
Be upbeat & encouraging
Reasonable expectations

Recommendations
If skill-focused:
then Computer
If algos-focused:
then Whiteboard
If a little of each:
then Either/or
 Both can work!
 … with proper training
 Whynot let candidate choose?

Thingsto Consider
 BarRaisersor Hiring Committees
 Code assessmenttools
 Pairprogramming(forpracticalstuff)
 Whiteboard(orpick-your-poison)foralgorithmsstuff

THANK YOU
gayle@gayle.com
gayle in/gaylemcdgayle

Architecture of Tech Interviews

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