Project ReportAn investigation on data entry effectiveness & efficiency

AgendaIntroductionExperiment DesignExperiment PlatformData AnalysisConclusion

Introduction Developing fast and efficient means

for text entry is one of the most pressing research topics in today!

Although the QWERTY layout is entrenched for physical keyboards, soft keyboards are easy to implement and customize.

Objective To develop a statistically reliable

analysis of possible factors that may have influence on the input efficiency and error rateof the soft keyboard and give design guideline on this issue.

Response variablesAverage typing speedError rate

Cause–and-effect Diagram

Control variablesKeyboard layoutKey size Key shapeMouse C/R ratio

Keyboard layout

Other Control FactorsKey size Large: the size of keys on

standard physical keyboard Small: that of general

electronic dictionaries

Mouse C/R ratio High: the highest in the

tested computer. Low: adjusted one which is

the lower bound that one can bear

Key shape There are three

kinds of key shape generally, but we choose two of them for simplicity: circle and square, the rest is hexagon

Learning Curve for Novice

Experiment Design(1/3)Mixed Level Full Factorial Design

Repleicated on two testeesEach testee enters the same

paragraph of text with different combinations of control factors

Experiment Design(2/3)

Experiment Design(3/3)Block On Noise Variables

Data within each block is homogenous (exclude the potential influence of different users)

Enough DOF to Estimate InteractionsEliminate Learning Effect

Two replicates with different (randomly generated) execution sequence

Platform(1/4)Large-SmallHigh-LowFITALY-OPTI II-

METROPOLIS-QWERTY Square-Circle.

There are 16 different types of soft keyboard in all.

Platform(2/4)

FITALY OPTI II

METROPOLIS QWERTY

Platform(3/4)

Platform(4/4)Saved in CSV filesKey name, x-

coordinate, y-coordinate, the time when it is entered

Errors: number of “Backspace”

Discussion on Error RateErrors may not be noticed immediately.Sequence of the words or letters may

be changed, due to other reasons unrelated to the keyboard.

Click “Backspace” when ever testee notices error and count the number of “Backspace” clicked as error

AnalysisTools

DOE++Minitab

Two Kinds of ResponsesTimeError rate

PrincipleTreat different responses separatelyFind an integrative optimal solution

Response TimeData Analysis

Step 1: ANOVAThe main effect is

significant

Step 2: RegressionIgnore the 3 or

higher order effectsKeep the significant

items

Step 3:Probability PlotReliaSoft DOE++ - www.ReliaSoft.com

Normal Probability Plot of Effect

Alpha = .1Standardized Effect (T Value)

Prob

abilit

y

-6.000 6.000-3.600 -1.200 1.200 3.6001.000

5.000

10.000

50.000

99.000

B[1]

B[2]

B[2]CD

A:Size

B[3]Effect Probability

TimeY' = Y

Non-Significant EffectsSignificant EffectsDistribution Line

宁毅清华大学2008-6-810:26:49

Step 4: Eliminate Insignificant factors

Keep A, B1, B2, B3

Step 5: Residual Checking

Step 6: Interaction Matrix

ConclusionTime will be shorter when

factor size= 2(larger size)factor layout=1(qwerty), and then 4(FITALY),

2(metro), 3(OPTI)The factor shape and C/R ratio will not influence

the result if the response is time

Error RateData Analysis

Step 1: ANOVAThe main effect is

significant

Step 2: RegressionIgnore the 3 or higher

order effectsKeep the significant

items

Step 3: Probability Plot

Step 4: Eliminate Insignificant Factors

Keep B1, AB1, AB2, C

Step 5: Residual Checking

Step 6: Interaction Matrix

ConclusionIt is more reasonable to choose factor size=

2(larger size)Hence factor layout = 4(FITALY) will be chosen

when the size=2The factor C/R ratio=1(low) will be betterFactor shape has no effects

Final RecommendationLarger sizeFITALY layoutLow C/R ratioBoth shapes

Potential WeaknessLimited Sample Size

Both Young Female University Students

Familiar with QWERTYWithout Upper CaseLimited to English Text

Q&A

Thank you