PairProgrammingintheClassroom

MarkSherriff

UniversityofVirginia

June29,2016

SomematerialcourtesyofLaurieWilliams,NCSU

Tapestry2016

Tapestry2016

Overview

• WhatexactlyisPairProgramming?

•  TheCaseforPairProgramming

•  TheCosts•  Guidelinesforasuccessfulpairingexperience• MythsandLegends

•  Resources

2

Tapestry2016

PairProgrammingDefiniQon

•  "Pairprogrammingisastyleofprogrammingin

whichtwoprogrammersworkside-by-sideat

onecomputer,conQnuouslycollaboraQngon

thesamedesign,algorithm,code,ortest."

–LaurieWilliams

3

Tapestry2016

SlightlyAlteredDefiniQon

•  "Pairprogrammingisastyleofprogrammingin

whichtwoprogrammersworkside-by-sideat

onecomputer,conQnuouslycollaboraQngon

thesamedesignoralgorithm."(emphasismine)

•  Basicidea:IDE’shelpuscode–peoplehelp

usdesign!

4

Tapestry2016

WhyPairProgramming?

•  Pairprogrammingstudentstendto:

– Makeitthroughthefirstclass

–  ImprovesretenQon

–  Increasesprogrammingconfidence

–  Performcomparablyorbe`eronexamsand

projects

–  Performjustfineinfuturesoloprogramming

– Helpcreatepeergroups

5

Tapestry2016

WhyPairProgramming?

•  Aninstantsupportsystem

– Wehavefoundthatpairingcutsdownonalarge

numberofthe"trivial"quesQons(syntax,

assignmentclarificaQon,etc.)andafairnumberof

themorecomplexquesQons(debugging,etc.)

– WehavebeenabletoreducethenumberofTAs

forsomecourses

–  Instructorofficehoursaremuchquieter,andthe

instructorcanspendmoreQmewithstudentsthat

needmorehelp

6

Tapestry2016

WhyPairProgramming?

•  SomeQmesitisanumbersgame

•  Inalabof40students…–  having20pairsmakesiteasierforTAstogetto

everyone

–  20assignmentsareeasier/fastertogradethan40

•  OurmainCS1coursehasonaverage500

studentsasemester…

7

Tapestry2016

TheRoles

•  TheDriver–  Thepersonwith"control"ofthecomputer

– Doesthebulkofthetyping•  TheNavigator

– AcQvelyfollowsalongwiththedriverwithcomments

–  CantakeoveratanyQme

•  Howdoesthistranslatetopairdesign?

8

Tapestry2016

Partnersvs.PairProgramming

•  HowisPairProgrammingdifferentthanjust

havingpartnerassignments?

– Mentalityofhowtoapproachtheassignment

•  Partnering:–  "YougodothispartandI’llgodothispartandthenwe’llputitbacktogether."

•  PairProgramming:

–  "Let’sfirstdothisparttogether,thenwe’lltackletherest."

9

Tapestry2016

Partnersvs.PairProgramming

•  ThedisQncQonma`ers!

•  Itma`ersto:

–  Instructors–  TeachingAssistants/Tutors–  Students

•  Callitframing,percepQon,spin…whatever

•  It’sallaboutajtude!

10

Tapestry2016

It’sAllAboutAjtude

•  Howdoyougettheajtudegoing?

•  HowdoIstartusingpairprogramming?

•  Thingstoconsider:–  TeachingtheTechnique– Assignments

–  PairCreaQon–  PairEvaluaQon– Assessment

11

Tapestry2016

TeachingtheTechnique

•  StartwiththeinstrucQonalstaff•  PairprogrammingHAStobeincorporatedinto

theclass(orlab)insomestructuredway

•  Studentsdonotnaturallyworkasa“pair”whengivena“partner”

• Whathappenswhenyoutellstudentstheycan

workwitha“partner”?

12

Tapestry2016

TeachingtheTechnique

•  Theenvironmentma`ers!

13

Tapestry2016

TeachingtheTechnique

• Whatareyouactuallyteachingthemtodo?

•  1.Taketurnsbeingtheonecoding(“driver”)•  2.Whoeverisnotcoding,commentacQvely

•  3.Whoeveriscoding,talkthroughwhatyou

aredoing

•  4.Switchatregularintervals•  5.Nothingisdoneindependentlyfromthe

otherpartner

14

Tapestry2016

TeachingtheTechnique

•  SwitchingrolescanbeproblemaQcs

•  Someideas:

– Goaroundandtappeopleontheshoulder– Haveaaudiocue– Haveavisualcue

•  Trytoenforceevenrolesasmuchaspossible

•  Trytoenforceno“splijngupwork”asmuch

aspossible

15

Tapestry2016

Assignments

•  DoIhavetototallychangemycoursematerial

todopairprogramming?

•  Answer:Probablynot,butsomechangesmight

makethingsgobe`er

16

Tapestry2016

Assignments

•  Biggestproblem:assignmentscope

•  Ifyouuseyourcurrentassignmentswithno

modificaQonatall,it’spossiblethatno

switchingwilloccurand/orthepointofpairing

won’tbeobvious

•  Example:ConvertFahrenheittoCelsius

•  CounterArgument:Twonoviceslearning

togetherfromtheverybeginningcouldhelp

withself-confidence

17

Tapestry2016

Assignments

•  Iftheassignmentscopeistoolargeorifthere

isanobvious“splitpoint”,divideandconquer

becomesmoretempQng

•  Example:WriteaStudentandCourseclassthat

worktogethertokeepupwithcourse

enrollment

18

Tapestry2016

Assignments

•  AnassignmentIlikeforpairprogramming:

•  EmailHunt

– Givenawebsitethathasabunchofemail

addressesonit,writeaprogramthatcanreadthe

websiteandextracttheemailaddresses

–  h`p://cs1110.cs.virginia.edu/emails.html

•  ThingsIlike:– Noonewaytodoit(infact,ittakesmorethanone

ideatogetalltheemailsout)

– AllowsforsomecreaQvity

19

Tapestry2016

PairCreaQon

•  Howdoyoucreatepartners?•  BigphilosophicquesQon:

– Doyouassignpartnersordoyouletstudentspicktheirownpartners?

– Advantagesanddisadvantagestoboth

20

Tapestry2016

PairCreaQon–AssignedPairs

•  Howcanyouassignpairs?–  Randomly

–  Basedonprogrammingexperience/confidence

–  Personality/friendships– Otherinterests/surveyresults

21

Tapestry2016

PairCreaQon–AssignedPairs

•  Randomly

–  Easiesttosetup– GoodifyouhavenootherinformaQontowork

from

– HaspotenQaltoleadtoproblems(butnotasmany

asyoumightthink)

–  Consider“randomwithreplacement”for

subsequentassignments(noonecanworkwith

samepersontwice)

22

Tapestry2016

PairCreaQon–AssignedPairs

•  Basedonprogrammingexperience/

confidence

–  Researchindicatesthishasthehighestlikelihoodofproducinggoodpartnerships

– HardtosetupunQlyouhavedata–  Eventhen,itcanbedifficultbecauseresearch

showsthatpercep)onofpartner’sability(notactualability)isahigherindicatorofagoodmatch

23

Tapestry2016

PairCreaQon–AssignedPairs

•  Personality/Friendships– Mostlikelytohavethefewestpersonalityconflicts

–  Enforcingcliques•  Othersurveyresults

–  Ihaven’tusedanythingelse,butcouldimagine

usingthingslike:

• Schedule• Outsideinterests• Commonfriends

24

Tapestry2016

PairCreaQon–Self-SelectedPairs

•  Self-selectedpairsopenhaveelementsofthe

assignedpairingswithsimilarexperienceand

friendships

•  Soithassimilarbenefitsanddrawbacks

•  However,youHAVEtomonitorcloselyforthe

“laststudentpicked”problem

•  Probablyshouldenforcereplacementforlater

assignments

25

Tapestry2016

PairReplacement

•  ReassignseveralQmespersemester

•  Goodforstudents– Gettomeetnewpeople,learnaboutworkingwith

newpeople

–  Iftheydon’tliketheirpartner,theyknowtheywillgetanewonesoon

•  Goodforinstructor– MulQpleformsoffeedback

– NaturalhandlingofdysfuncQonalpairs

26

Tapestry2016

PairManagementandEvaluaQon

•  Auto-AssignPairCreaQon–  CATME–h`p://www.catme.org

– Dataneededtoauto-createpairsvaries•  Self-ReportedPairs

– GoogleForms

27

Tapestry2016

PairEval

28

Tapestry2016

PairEval

29

Tapestry2016

PairEvaluaQon

• Withorwithoutatool,itboilsdowntoafew

quesQons:

– Didthepairgetalong?– Didyougettheworkdone?– Doyoufeellikeyou“didyourfairshare?”

• Moredataisnice/interesQng,butthisisallyou

reallyneed

•  Reliablefeedbacksystemisneeded(bothfor

youandthestudents)

30

Tapestry2016

PairEvaluaQon

•  NCWITresourceshavesurveysyoucanuse!

•  Exampleinyourpacket

•  h`p://www.ncwit.org/pairprogramming

31

Tapestry2016

PairEvaluaQonandAssessment

•  Ifthere’snoproblem…thengreat!

•  Ifthereis…–  Ifpossible,askthestudentsoneataQme:“If100%

effortisyoudoingexactlywhatyoushouldhave

beendoing,whatpercentagedidyouactuallydo?”

–  95%oftheQme,thisworks!

–  Fortheother5%,youhavetouseyourbestjudgement

32

Tapestry2016

Assessment

•  Forotherclassassessments,Idonotadjust

anything

•  Alltests/exams,popquizzes,etc.allstaythe

sameasifitwereasoloprogrammingonly

course

33

Tapestry2016

TheBiggestCost

•  Training!•  Instructors,TAs,andstudentsneedtobetaughthowtodoeffecQvepairprogrammingin

acontrolledenvironment!

•  Thecontrolledenvironmentcouldbeaclosed

laborlecture-labsystem

34

Tapestry2016

Butwedon’thaveaclosedlab?

•  CS1:–  Assignedpairsnotadvisableiftheydon’tknowthepartnersTrytointroduceinguidedlabs/in-classacQviQesfirst

•  CS2:–  ProceedwithcauQonforassignedpairsforfirstassignment

–  Worksbe`eraperfirstmonthorso

–  Atleastbondinlab+someoutsidework

•  CS2+:–  Aperatleastonepairedclass –  BondingsQllbeneficial,outsideworkfine

35

Tapestry2016

GejngInvolved

•  InstructorsandTeachingAssistantshavetotakeanacQveroleinlab

– Mustmonitorandapproachpairsiftheyseemto

bedysfuncQonal

–  Should"stronglyencourage"driversandnavigatorstoswitch

•  Instructorsalsomustunderstandthatsome

pairingsarejustnotgoingtowork

– Don’tletitdiscourageyou!

36

Tapestry2016

HowManyPairingsFail?

37

Class Very compatible

OK Not compatible

CS1 64% 32% 4%

SE-P1 60% 33% 7%

SE-P2 56% 35% 9%

OO 76% 15% 9%

Total 60% 33% 7%

Tapestry2016

ProblemPairs

• Willproblempairshappen?Yes.

•  ParQcularcases:–  The“Idon’tcare”student–  Thespecialneedsstudent–  Theabsentstudent–  The“liberalartsvs.engineering”student

•  Theseproblemsarenotpairprogramming

related,butpairprogrammingcanmakethese

cometothesurfacemoreopen

38

Tapestry2016

GuidelinesToFollow

•  Stricttardiness/absencepolicymustbe

followedforpairacQviQestoguardagainstlazy

partners.

–  Lossofpartner,points,andbadevaluaQon•  TheremustbeareporQngmechanismfor

studentstoprovidefeedbackonpartners

–  CATMEorasimpleGoogleForm

–  "Ifyoucouldrateyoureffortbasedon100%.."

39

Tapestry2016

GuidelinesToFollow

•  Assignmentsshouldbeabitmorechallenging

–  "Sopball"assignmentstendtobefinishedbya

singlepersonwithoutconsulQngtheirpartner

•  Theenvironmentforpairingmustbeconducive

topairing

40

Tapestry2016

GuidelinesToFollow

•  Don’tgooverboard!–  EverythinginmoderaQonJ

–  Pairingisn’tforeveryassignment

–  Theremustbeabalance(inworkandingrade)

41

Tapestry2016

MythsandLegends

• Myth:Halfthestudentswilllearn–  "Inthefirstcourse,studentsneedsome)metoabsorbtheideasthemselves."

–  "Myinclina)onistoallowmoregroupworkstar)nginthesecondcourse."

–  "Wewanttobesurethateachstudentwritesenoughcodehim/herselftolearntheintroductoryconcepts."

–  "Iamagainstpair-programminginintroductorycourses,wherestudentsneedtodevelopstrongprogrammingskillsthemselves."

42

Tapestry2016

MythsandLegends

•  Infact,allthestudentslearnpre`ywell…–  StudiesatNCSUandSDSUshowedthatexam

scoreswerecomparableorimprovedforall

studentsinintroductoryclasses

– Also,thepercentageofstudentswhosegradeinCS2wentdownbyover1/3ofagradedropped

oncepairingwasusedinCS1

Williams,L.,Layman,L.,

LabPartners:IfThey’reGoodEnoughfortheSciences,WhyAren’tTheyGoodEnoughforUs?,

ConferenceonSopwareEngineeringEducaQonandTraining(CSEE&T’07)

43

Tapestry2016

MythsandLegends

•  Byfallingforthismyth,you’reperpetuaQng

anotherone

–  “AllcomputerscienQstworkbythemselvesin

cubiclesstrugglingtocode.”

• WeallknowthatcreaQngsopwareisHIGHLY

collaboraQve!

• Whygivethewrongimpressioninthefirst

classtheytake!?

44

Tapestry2016

MythsandLegends

• Myth:CheaQngwillincrease–  "Withlooserulesaboutwhopartnersare,peoplewilljustpasscodearound.Therehastobestructure!"

–  "Oldpartnersmayfeelobligedtohelptheirformerteammates."

45

Tapestry2016

MythsandLegends

•  Thinkaboutitali`ledifferently…• Whenweprovidepartners,studentsnowhave

asupportsystemtheycanturnto

– Anecdotalevidencefromstudentsindicatedthat

thestressoffeelingaloneandisolatedmadethem

considercheaQng

•  TwopeoplenowhavetoagreeoncheaQng!– Well…thereareexcepQonstothisone…

– Mossandetectorarevaluabletools

46 Tapestry2011

Tapestry2016

OtherGuidelinesandMyths

•  Anyotherstoadd?

47 Tapestry2011

Tapestry2016

Resources

•  h`p://www.realsearchgroup.org/pairlearning•  h`p://www.ncwit.org/pairprogramming

• Mypersonalwebsite:

h`p://www.cs.virginia.edu/~sherriff

• Myemail:sherriff@virginia.edu

48 Tapestry2011