The keystroke-level model for user performance time with interactive systems

There are ~eg:N ms:poets of aser~emt,xu{er ~rforma~ce tha~ sys*em designers sh~d sys~emarka{~ ~ e r. This arlic|e prop~yses a ~im~}e m~eL the Neys{T{.>ke-Levd Medea, for predkd~g o,~e aspe~'t M w2rferma:mee: the time i:t takes ,a~ expel u~wr ~;:o perform a givers *az~ m~ a give= eom,p~:{er sys{~a. The model is b.ae~ e~ counting keystrokes :a~d @~er |owdevel operatkms., i:~c{udir~g the user's ~me=taI ~re~aratioas arid the* system's re Pe e is coded fa ~¢~ge~ of ~e~e {~*rati~as an.d epe~a~r Nm¢~ s~:~ Ce Nve Ne~c~i~s,~ HeurNfic n~}es are :gh'ef~ Nr p'redicti~g ~here men~al prelaara~ie~s ¢~ce~r. When tested against{ data ¢m 1|) diffe:re~ systems, ~N~I's pee~ic~ifye e~f N 2t ~reem fee tMividual ~asks.. A= examNe N gia'ee m Rlus{ra{e h(~ NEe m~l .eaa ~ ~aed to pr~dece parametric predie{km.g add brow set~:sifivt{y aaaiysis c:a:a be ~:sexi m redeem ce~e|~.sfo~s in the face of ~mc,e~aia as:sumt~ti~o~:s, Finally, the model ~s e@m~ar~ ~o ~ereral s*mp|er ver,s&ms. "INe N, ter~fiaJ fete ~k~r ~he Keystroke*Level Model i.n gys{em de:skgn is Fhe dcsigs and evaluation of imeracti,~e computer systems sho~ald ~ake imo accnun~ ~he ~o~a! per~brma~<e of the combit~ed ~serocompu~er system. Such an at<:ou~ woukJ reflcc~ the psychological charac~eristic.~ of users and ~heir imerac~ion wish {he ~ask and the computer. This rarely ncc~.:~rs in any sss~ematic and explicit way, The causes of this fl~ilare may lie partly in amt~de:; ioward doe ~ibi~i~y of dealing s~ccesduily with psy~. chok}gicM factors, such as the belief @m~ i~mmion~ s~,b~ ]ective eaperiesce~ sad anecdote ~brm the only possible bases ff:,r deMing wif~ ~hem Whatever may be ~rue ot' ~hcae more gk:>bat iss:ues~ oae major cau:se is the ab:>ence of g<xxJ analysis ~ools for a,::_~:ssiag combined user.,<om-purer performance. There exists quite a bit of research retevan~ to ~he area of user-computer performance, b~ mo:s~ of it is preIiminary is m~ture. Pew et aL [14t ia a review o{ ¢3 g<r~e~'~fiaIIy relevant haman-system pertbrmar~ce models~ co~achade "~ha~ is~egrative models of huma~~ p<r%rmance compa~iNe with the requirements ~br representing cors-mand and comrol system ~rR>rmance do so~, exist a~ the present @he." Ramsey and A~w~.x>d {/51~ after reviewing the human L~c~ors literature pertb~em to computer sys-tem:s, conclude 1hat while ~here exists eno~gh material ~o develop a qualitative 'human factors design guide," ~here is i.asufficient material ~br a "quantitative reference hand book2' This paper presents one s~scific quanti~aive analysis took a simple model for the time it takes a user ~o perform a task wi~.h a given …