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Why does the spreadsheet work … … and how can we improve it? A user interface perspective on the foundations of spreadsheets. Alan Blackwell Computer Laboratory Cambridge University. Outline. Why the spreadsheet was invented Which features were critical to success
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Why does the spreadsheet work … … and how can we improve it?A user interface perspective on the foundations of spreadsheets. Alan BlackwellComputer LaboratoryCambridge University
Outline • Why the spreadsheet was invented • Which features were critical to success • HCI research in spreadsheet use • Where next? • Grounds for critique of current products • Possible product futures • Possible futures for spreadsheet users
Timescale of UI Evolution • 1940s:Scientific instruments
DIMENSION A(11) READ A 2 DO 3,8,11 J=1,11 3 I=11-J Y=SQRT(ABS(A(I+1)))+5*A(I+1)**3 IF (400>=Y) 8,4 4 PRINT I,999. GOTO 2 8 PRINT I,Y 11 STOP Timescale of UI Evolution • 1940s:Scientific instruments • 1950s:Mathematical tools
Timescale of UI Evolution • 1940s:Scientific instruments • 1950s:Mathematical tools • 1960s:Data files & records
OBEY YES SIR Timescale of UI Evolution • 1940s:Scientific instruments • 1950s:Mathematical tools • 1960s:Data files & records • 1970s:Command languages
Timescale of UI Evolution • 1940s:Scientific instruments • 1950s:Mathematical tools • 1960s:Data files & records • 1970s:Command languages • 1980s:Bitmapped screens, direct manipulation
“Modern” UI Essentials • Drawing • e.g. Sketchpad 1963
“Modern” UI Essentials • Drawing • e.g. Sketchpad 1963 • Presentation • e.g. NLS 1968 • (also hypertext, online collaboration …)
“Modern” UI Essentials • Drawing • e.g. Sketchpad 1963 • Presentation • e.g. NLS 1968 • (also hypertext, online collaboration …) • Word Processing • e.g. Bravo 1973-77
Inventing the Spreadsheet (1978) • Bricklin’s concept: • “electronic blackboard” • closest to NLS collaboration tools? • Frankston’s optimisation: • fast, compact & responsive • Fylstra’s market: • individual ownership and control via PCs
Outline • Why the spreadsheet was invented • Which features were critical to success • HCI research in spreadsheet use • Where next? • Grounds for critique of current products • Possible product futures • Possible futures for spreadsheet users
From Apple II to IBM PC / MS-DOS • PC Functionally equivalent to the Apple II • (no mouse, no bitmapped display) • Business software emphasis • simple databases • word processing • Lotus 1-2-3 replaced VisiCalc, included charts and plots (as well as some database and text formatting)
Direct manipulation • Original Mac applications were “creative” • writing, drawing, painting • derived from Kay’s vision of creative machine • Business market developments • desktop publishing created business market • Apple asked Microsoft to develop a SS • Excel • offered direct manipulation benefits of the Mac • point and click, menus, windows, prompts
The Spreadsheet “Metaphor” • HCI textbooks propose metaphor as starting point for UI design. • But there is little evidence that the paper SS ever influenced the development of SS software. • Most benefits historically derived from UI features of other software categories.
Outline • Why the spreadsheet was invented • Which features were critical to success • HCI research in spreadsheet use • Where next? • Grounds for critique of current products • Possible product futures • Possible futures for spreadsheet users
Experimental extensions • UI builder functions (Myers) • Navigation aids (Rao & Card) • Debugging aids (Burnett et. al.) • Typing and inference (Erwig) • Gesture interfaces (Wolf, Burnett) • Approximation, graphics (Lewis) • Multi-user support (various) • Tutoring and help systems (various) • Voice interfaces (various)
Spreadsheets in end-user context • Bonnie Nardi, A Small Matter of Programming (MIT Press 1993) notes: • SSs are immediately useful for real tasks • SSs support direct manipulation • SSs have limited control constructs • SSs lead to collaborative communities • But SSs are: • Not automatically easy to learn (Hendry & Green) • Liable to contain errors (Panko, others)
Mental models of spreadsheets • The user’s “mental model” is critical in HCI • But hard to say what goes on inside a programmer’s head! • Saarilouma & Sajaniemi (1989) showed SS users employ visual images • Navarro Prieto (1998) found visual images help SS users understood dataflow • Petre & Blackwell (2000) note that many programmers report experiencing images
Some theoretical design principles • Cognitive Dimensions of Notations • Discussion vocabulary for significant design attributes and tradeoffs • (see Green & Petre in JVLC 1996, Blackwell & Green in Carroll, ed. 2003.) • Surprise, Explain, Reward • We’ve built it, but will they come? • (see Robertson et. al., CHI 2004) • See also Blackwell’s Attention Investment theory of abstraction use
Outline • Why the spreadsheet was invented • Which features were critical to success • HCI research in spreadsheet use • Where next? • Grounds for critique of current products • Possible product futures • Possible futures for spreadsheet users
Lessons from history & research • Account for collaboration • Be fast and responsive • Empower individuals • Provide a flat, imageable world • Support direct manipulation • Do current products retain these benefits?
Outline • Why the spreadsheet was invented • Which features were critical to success • HCI research in spreadsheet use • Where next? • Grounds for critique of current products • Possible product futures • Possible futures for spreadsheet users
Features are not the answer • Applications are developed in SSs because of their low entry cost, seldom on engineering grounds. • 57% of 5500 SSs had no formulas • Can SS functions be partitioned into developer and end-user sets? • How would the transition be managed? • Can we provide engineering benefits to end users? • EUSES, e.g. Burnett, Erwig, Blackwell
Outline • Why the spreadsheet was invented • Which features were critical to success • HCI research in spreadsheet use • Where next? • Grounds for critique of current products • Possible product futures • Possible futures for spreadsheet users
User simplification • If the SS has been moving away from its roots, can users (or organisations) return? • Templates • Process definitions • Reduced-feature standards • Adapt open-source products • Any more options? (DISCUSS!)