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Designing Accurate
Data Entry Procedures
Systems Analysis and Design, 7eKendall & Kendall
15
2008 Pearson Prentice Hall
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Learning Objectives
Understand the uses of effective coding tosupport users in accomplishing their tasks
Design effective and efficient data captureapproaches for people and systems Recognize how to ensure data quality
through validation
Articulate accuracy advantages of userinput on ecommerce Web sites
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Accurate Data-Entry Objectives
Effective coding
Efficient data capture
Effective data capture
Assuring data quality through validation
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Major Topics
Effective coding
Types of codes
Guidelines for coding
Validation methods
Check digits Ecommerce accuracy
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Effective Coding
Data that are coded require less time toenter
Coding helps to reduce the number ofitems entered
Coding can help in sorting of data
during the data transformation process Coded data can save valuable memoryand storage space
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Human Purposes for Coding
Keeps track of something
Classifies information
Conceals information
Reveals information
Requests appropriate action
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Simple Sequence Codes
A number that is assigned to somethingif it needs to be numbered
No relation to the data itselfFigure 15.1 Using a simple sequence code
to indicate the sequence in which orders
enter a custom furniture shop
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Simple Sequence Codes
(Advantages) Eliminates the possibility of assigning
the same number
It gives users an approximation of whenthe order was received
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Simple Sequence Codes
(Disadvantages) When you do not wish to have someone
read the code to figure out how many
numbers have been assigned When a more complex code is desirable
to avoid a costly mistake
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Alphabetic Derivation Codes
A commonly used approach inidentifying an account number
Figure 15.2 Identifying the account of a magazine
subscriber with an alphabetic derivation code
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Alphabetic Derivation Codes
(Disadvantages) When the alphabetic portion is small or
when the name contains fewer
consonants than the code requires Names like ROE - become RXX
Some of the data may change
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Classification Information
Affords the ability to distinguishbetween classes of items
Must be mutually exclusive
Classification codes
Block sequence codes
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Classification Codes
Used to distinguish one group of datawith special characteristics from another
Can consist of either a single letter or anumber
A shorthand way of describing a
person, place, thing, or event Listed in manuals or posted so thatusers can locate them easily
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Classification Codes
Use a single letter for a code
Figure 15.3 Grouping tax-deductible items
through the use of a one-letter classification
code
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Block Sequence Codes
An extension of the sequence code
Data are grouped according to commoncharacteristics
Simplicity of assigning the nextavailable number (within the block) to
the next item needing identification
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Figure 15.5 Using a block sequence codeto group similar software packages
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Concealing Information
Codes may be used to conceal ordisguise information
Cipher Codes
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Cipher Codes
The direct substitution of one letter foranother, one number for another, or
one letter for a number
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Figure 15.6 Encoding markdown prices with a ciphercode is a way of concealing price information fromcustomers
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Revealing Information
Sometimes it is desirable to revealinformation to specific users through a
code Makes the data entry more meaningful
for humans
Significant-Digit subset codes Mnemonic codes
Unicode
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Significant-Digit Subset Codes
Used to help describe a product byvirtue of its membership in many
subgroups Possible to locate items that belong to a
certain group or class
Inquiries may be performed on aportion of the code
Useful for a marketing product
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Figure 15.7 Using a significant-digit subset code helpsemployees locate items belonging to a particulardepartment
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Mnemonic Codes
A mnemonic (pronounced n-mn'-k) is ahuman memory aid
Any code that helps the data-entry personremember how to enter the data or the userremember how to use the information is amnemonic
Using a combination of letters and symbolsaffords a clear way to code a product so thatthe code is easily seen and understood
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Figure 15.8 Mnemonic codes function asmemory aids by using a meaningful combination
of letters and numbers
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Unicode
Includes all standard language symbols
Has room for 65,535 characters
The full set of Unicode characters aregrouped by language and may be foundat www.unicode.org
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Requesting Appropriate Action
Instruct either the computer or thedecision maker about what action to
take Function codes
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Function Codes
Short numeric or alphanumeric codesused to spell out precisely what
activities are to be accomplished
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Figure 15.9 Function codes compactly capturefunctions that the computer must perform
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General Guidelines for Coding
Be concise
Keep the codes stable
Ensure that codes are unique Allow codes to be sortable
Avoid confusing codes
Keep the codes uniform Allow for modification of codes
Make codes meaningful
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Be Concise
Overly long codes mean more keystrokes andconsequently more errors
Long codes also mean that storing theinformation in a database will require morememory
Short codes are easier for people to
remember and easier to enter If codes must be long, they should be brokenup into subcodes
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Keep the Codes Stable
Stability means that the identificationcode for a customer should not change
each time new data are received Dont change the codes in a mnemonic
system
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Ensure That Codes Are Unique
For codes to work, they must be unique
Do not assign the same code number or
name to the same items
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Allow Codes to Be Sortable
Make sure that users can do what youintend to do with the codes you create
Numerical codes are much easier to sortthan alphanumeric data
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Avoid Confusing Codes
Avoid using coding characters that lookor sound alike
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Figure 15.12 Combining look-alikecharacters in codes can result in errors
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Keep the Codes Uniform
Need to follow readily perceived forms
Keep codes uniform among as well as
within programs
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Allow for Modification of Codes
The system will evolve over time
The coding system should be able to
encompass change
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Make Codes Meaningful
Effective codes contain information
Should make sense to people using
them Easier to understand, work with, and
recall
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Using Codes
Validation programs
Report and inquiry programs
GUI programs
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Effective and Efficient Data
Capture Deciding what to capture
Letting the computer do the restAvoiding bottlenecks and extra steps
Starting with a good form
Choosing a data-entry method
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Deciding What to Capture
Data that change or vary with everytransaction
Data that concisely differentiate theparticular item being processed from allother items
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Letting the Computer Do the Rest
Recording the time of the transaction
Calculating new values from input
Storing and retrieving data on demand
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Avoiding Bottlenecks and ExtraSteps
Data are poured rapidly into the wide mouthof the system only to be slowed in its neck
because of an artificially created instance ofinsufficient processing for the volume ordetail of the data being entered
The fewer steps involved in inputting data,
the fewer chances there are for theintroduction of errors
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Starting with a Good Form
With effective forms, it is not necessaryto reenter information that the
computer has already stored, or datasuch as time or date of entry that thecomputer can determine automatically
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Choosing a Data-Entry Method
Keyboards
Optical character recognition
Magnetic ink character recognition
Mark-sense forms
Bar codes
RFID
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Keyboards
Special function keys to open programs
Keys used to scroll and explore the Web
Keys that can be programmed withmacros to reduce the number ofkeystrokes required
Ergonomic keyboards and infrared orBluetooth-enabled keyboards
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Optical Character Recognition
Increased speed
Eliminates many of the time-consuming and
error-fraught steps of other input devices Decentralizes responsibility for quality data
directly to the unit that is generating it
The transformation of faxes into documentsthat can be edited
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Magnetic Ink CharacterRecognition
A reliable and high-speed method that is notsusceptible to accepting stray marks
If it is required on all withdrawal checks, itserves as a security measure against badchecks
Data entry personnel can see the numbers
making up the code if it is necessary to verifyit
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Mark-Sense Forms
Little training of entry personnel is necessary
A high volume of forms can be processedquickly
Stray marks on form can be entered asincorrect data
Choices are limited to the answers provided
Difficulty in capturing alphanumeric data Easy to get confused and put a mark in an
incorrect position
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Bar Codes
Affords a high degree of accuracy fordata entry
Saves labor costsAllows the automatic capturing of data
Tracking of credit card purchases
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Figure 15.17 Bar coding, as shown on this label for groceryproduct, affords highly accurate data entry. Used with thepermission of the Uniform Code Council, Dayton, Ohio
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RFID
Allows the automatic collection of datausing RFID tags that contain a chip and
an antenna Passive RFID tags
Active RFID tags
Privacy is a concern
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Ensuring Data Quality throughInput Validation
The critical importance of catchingerrors during input, prior to processing
and storage cannot be overemphasized Potential problems
Validating input transactions
Validating input data
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Figure 15.18 Validating input is important toensure that most potential problems with dataare eliminated early
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Validating Input Transactions
Submitting the wrong data
Submitting of data by an unauthorized
personAsking the system to perform an
unacceptable function
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Validating Input Data
Test for missing data
Test for correct field length
Test for class or composition Test for range or reasonableness
Test for invalid values
Cross-reference checks Test for comparison with stored data
Setting up self-validating codes (check digit)
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Figure 15.19 Steps in converting a five-digitnumber to a six-digit number containing a checkdigit
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The Process of Validation
Check first for missing data
Check the syntax
Check the semantics
GUI screens can help to reduce thenumber of human input errors when
they incorporate radio buttons, checkboxes and drop-down lists
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The Process of Validation(Continued)
Regular expressions
Validating XML documents
DTD
Schema
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Figure 15.22 These characters are usedin regular expression (pattern) validation
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Accuracy Advantages inEcommerce Environments
Customers generally key or enter datathemselves
Data entered by customers are stored forlater use
Data entered at the point of sale are reusedthroughout the entire order fulfillment
process Information is used as feedback to customers
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Summary
Quality of data
Effective coding
Effective and efficient data capture
Validation of data
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Summary (Continued)
Coding Sequence codes
Alphabetic derivation codes
Classification codes
Block sequence codes
Cipher codes
Significant-digit subset codes
Mnemonic codes
Uniform character set
Function codes
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Summary (Continued)
Input devices Keyboards OCR
MICR Mark-sense forms Bar codes
Input validation
Input transaction Input data
Ecommerce