Systems analysis and design methods 7th whitten and benley chapter 12

Input Design and Prototyping
Introduction
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The chapter will address the following questions:
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What is the appropriate format and media for a computer input?
What is the difference between data capture, data entry, and data
input?
Can you identify and describe several automatic data collection
technologies?
How do you apply human factors to the design of computer inputs?
How do you design internal controls for computer inputs?
How do you design a good source document for capturing
transaction data?
How do you select proper screen-based controls for input attributes
that are to appear on a GUI input screen?

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Data Capture, Data Entry, and Data Input
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To input business data into a computer, the analyst may have to design
source documents, input screens, and methods and procedures for
getting the data into the computer.
Data accompanies business events called transactions.
Systems analysts must determine when and how to capture the data.
 Data capture is the identification of new data to be input.
 It's always best to capture the data as soon as possible after it is
originated.
Traditionally, special paper forms called source documents were used
to capture the data.
 A source document is a paper form used to record data that will
eventually be input to a computer.
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Input Design and Prototyping
Methods & Issues for Data Capture

& Input
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Data Capture, Data Entry, and Data Input
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Traditionally, special paper forms called source documents were used
to capture the data.
 A source document is a paper form used to record data that will
eventually be input to a computer.
With advances in video display technology, screen display forms are
able to duplicate the appearance of almost any paper based form.
 Screen display forms and source documents must be designed to be
easy for the system user to complete and should facilitate rapid
data entry.
• Data entry is the process of translating the source document into a
machine-readable format. That format may be a magnetic disk, an
optical-mark form, a magnetic tape, or a floppy diskette, to name a few.

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Data Capture, Data Entry, and Data Input

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Data input is performed after data entry.
 Data input is the actual entry of data in a machine-readable
format into the computer.

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Modern Input Methods: Batch versus On-Line Inputs
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Input methods can be broadly classified as either batch or on-line.
 Batch input is the oldest and most traditional input method.
Source documents or forms are collected and then periodically
forwarded to data entry operators, who key the data using a
data entry device that translates the data into a machinereadable format.
 The most common medium for batch input data are Key-todisk (KTD) and key-to-tape (KTT) workstations that
transcribe data to magnetic disks and magnetic tape,
respectively.
• The data can be corrected, because it is initially placed into a
buffer.
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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Modern Input Methods: Batch versus On-Line Inputs
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Today, most, but not all, systems have been converted or are being
converted to on-line methods.
 On-line input is the capture of data at its point of origin in the
business and the direct inputting of that data to the computer,
preferably as soon as possible after the data originates.
 The on-line system includes a monitor screen and keyboard
that are directly connected to a computer system.
 Most new applications being developed today consists of
screens having a “graphical” looking appearance called a
graphical user interface (GUI).

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Modern Input Methods: Batch versus On-Line Inputs
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Today, most, but not all, systems have been converted or are being
converted to on-line methods.
 Remote batch offers on-line advantages for data that is best
processed in batches. The data is input on-line with on-line
editing. Microcomputers or minicomputer systems can be used
to handle this on-line input and editing. The data is not
immediately processed. Instead, it is batched, usually to some
type of magnetic media. At an appropriate time, the data is
uploaded to the main computer, merged, and subsequently
processed as a batch. Remote batch is also called deferred
batch or deferred processing.

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Trends in Automatic Data Collection Technology
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Using today's technology, most if not all human intervention
associated with the input methods previously discussed can be
eliminated.
 By eliminating human intervention, the time-delay and errors
associated with human interaction can be decreased.

Biometric:
 Biometric ADC systems consist of sensors that capture an
individuals characteristic or trait, digitizes the image pattern,
and then compares the image to stored patterns for
identification.
 Biometric ADC are popular because they offer the most
accurate and reliable means for identification.
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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Trends in Automatic Data Collection Technology
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Electromagnetic:
 Electromagnetic ADC technology is based on the use of radio
frequency to identify physical objects.
• This technology involves attaching a tag and antenna to the
physical object that is to be tracked.
• The tag contains memory that used to identify the object that is
being tracked.
• The tag can be read by a reader whenever the object resides within
the electromagnetic field generated by the reader.

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Trends in Automatic Data Collection Technology
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Magnetic:
 Magnetic ADC technology involves using magnetic stripe
cards, but also may include the use of magnetic ink character
recognition (MICR).
 MICR is most widely used in the banking industry.

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Trends in Automatic Data Collection Technology
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Optical:
 Bar coding is an example of optical technology.
• Sophisticated laser readers read the bar code and send the data
represented by that code directly to the computer for processing.

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The optical-mark form is another example of optical technology.
• The source document becomes the input medium.
• The source document is directly read by an optical-mark reader
(OMR) or optical-character reader (OCR).
• The computer records the data to magnetic tape, which is then input
to the computer.
• OCR and OMR input are generally suitable only for high-volume
input activities.

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Trends in Automatic Data Collection Technology
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Smart Cards:
 Smart card technology has the ability to store a massive
amount of information.
 Smart cards are similar, albeit slightly thicker, than credit cards.
• They also differ in that they contain a microprocessor, memory
circuits, and a battery.
• Smart cards are used on a daily basis by over 60% of the French
population.

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Trends in Automatic Data Collection Technology
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Touch:
 Touched-based ADC systems include touch screens, buttons,
and pen-based computing technology.
 Touch screen technology has been very popular in restaurant or
point-of-sale business applications.
 Pen-based computing is popular for applications that require
handwriting recognition.

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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System User Issues for Input Design
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Inputs should be as simple as possible and designed to reduce the
possibility of incorrect data being entered.
The following general principles should be followed for input
design:
 Capture only variable data.
 Do not capture data that can be calculated or stored in
computer programs.
 Use codes for appropriate attributes.

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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System User Issues for Input Design
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If source documents are used to capture data they should be easy
for system users to complete and subsequently entered into the
system.
The following suggestions may help:
 Include instructions for completing the form.

 Minimize the amount of handwriting.
 Data to be entered (keyed) should be sequenced so it can be
read like this book, top to bottom and left to right .
 Ideally, portions of the form that are not to be input are placed
in or about the lower right portion of the source document.

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Input Design and Prototyping
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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Internal Controls for Inputs
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Internal controls are a requirement in all computer-based systems.
Input controls ensure that the data input to the computer is
accurate and that the system is protected against accidental and
intentional errors and abuse, including fraud.
The following internal control guidelines are offered for inputs:
 The number of inputs should be monitored.

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Internal Controls for Inputs
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The following internal control guidelines are offered for inputs:
(continued)
 Care must also be taken to ensure that the data is valid.
• The following techniques are widely used to validate data:
– Completeness checks determine whether all required fields on
the input have actually been entered.
– Limit and range checks determine whether the input data for
each field falls within the legitimate set or range of values
defined for that field.
– Combination checks determine whether a known relationship
between two fields is valid.

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Input Design and Prototyping
Methods & Issues for Data Capture
& Input
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Internal Controls for Inputs
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The following internal control guidelines are offered for inputs:
(continued)
 Care must also be taken to ensure that the data is valid.
• The following techniques are widely used to validate data:
(continued)
– Self-checking digits determine data entry errors on primary
keys. (see following figure)

– Picture checks compare data entered against the known
COBOL picture or other language format defined for that data.

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Data validation requires that special edit programs be written to
perform checks.

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Input Design and Prototyping
MODULUS 11
The following procedure is used to assign a check digit to a key field:
STEP 1: Determine the size of the key field in digits.
2 4 1 3 5 = 5 digits
STEP 2: Number each digit location from right or left beginning with the number “2.”
24135
65432
STEP 3: Multiply each digit in the key field by its assigned location number.
2 X 6 = 12
4 X 5 = 20
1X4=4
3X3=9
5 X 2 = 10
STEP 4: Sum the products from step 3.
12 + 20 + 4 + 9 + 10 = 55
STEP 5: Divide the sum from step 4 by 11.
55/11 = 5 Remainder 0
STEP 6: If the remainder is less than 10, append the remainder digit to the key field. If

the remainder is equal to 10, append the character “X” to the key field.
241350

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Input Design and Prototyping
GUI Controls for Input Design
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Introduction
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Most new applications being developed today include a GUI.
 This approach is influenced by a new trend in programming,
called repository-driven programming.

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Input Design and Prototyping

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Input Design and Prototyping

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Input Design and Prototyping
GUI Controls for Input Design
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Text Box
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A text box consists of a rectangular shaped box that is usually
accompanied by a caption.
A text box requires the user to type the data inside the box.
A text box can allow for single or multiple lines of data characters
to entered.

When a text box contains multiple lines of data, scrolling features
are also normally included.

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Input Design and Prototyping
GUI Controls for Input Design
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Text Box
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When to Use Text Boxes For Input:
 A text box is most appropriately used in those situations where the
input data values are unlimited in scope and the analyst is unable to
provide the user with a meaningful list of values from which they
can select.
Suggested Guidelines for Using Text Boxes:
 A text box should be accompanied by a descriptive caption.
• Avoid using abbreviations for captions.
• Only the first character of the caption’s text should be capitalized.
• The caption should be located to left of the actual text box or left-aligned
immediately above the text box.
• The caption should be followed by a colon to help the user visually
distinguish the caption from the box.
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