Input Controls

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Input Controls

• Chapter 11

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Input Controls

• Responsible for bringing both data and
  instructions into an application system
• Both types of input must be validated
• Errors detected and controlled so that input
  resubmission is accurate, complete, unique and
  timely.

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Critical to Auditor

• Largest number of controls auditors spend the
  most time on this area
• Error prone because the work is routine,
  monotonous and requires human intervention
• Target of fraud addition, deletion or
  alteration of input transactions

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Data Input Methods
Keyboarding
Personal computer
Recording medium
OCR MCR Mark Sensing Digitizer Image reader Point
of sale device ATM
Direct reading
State/Event
PC Touch Screen Mice Joystick Trackball Voice V
ideo Sound
Direct entry
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Data Input Methods

• Entered Directly
• Entered on Medium
• Data preparation Activities
• Pre-recording
• Post-recording
• Combination Methods

Human Intervention
Errors
Time elapsed before recording
Use of Input DevicesATM and POS
Errors
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Control Advantages of using Point-of-Sale
Terminals

• Optical scanning of pre-marked prices
• Customer verification of receipt
• Control over tender
• Automatic check authorization and credit/debit
  card processing
• Independent record of transactions
• Better Inventory control

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Control Advantages of Using ATMs

• Physical security over cash
• Maintenance of independent records of
  transactions
• Cryptographic facilities
• Software to guide customers through transactions

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Source Document Design
Business Processes
Information Processes
HardwareSoftware
AcquisitionConversionSales
Recording
SourceDocument
Delay
Events
Maintenance
Describe
Resources,Agents,Locations
Changein State
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Revenue and Collection Cycle
Source Document AnalysisWhat data? How is data
captured? Who will capture the data? How is
data prepared? How is data entered? How are
documents handled, stored and filed?
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Sales and Accounts Receivable Computer Processing
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Cash Receipts Processing
1
2
PrepareCRL
ApproveDiscounts
Startcash
Post Acc Rec
Prepare CRJ Post GL
Characteristics of the paper medium Length,
width, grade, weight, single or multiple
part Layout an Style of the Document Preprint,
highlighting, arrangement, captions, tick marks,
boxes, space, order, pre-number etc.
CRL
GL
AccRec
DS2
AccRec
DS1
To Bank
1
2
CRL3
Money
CRL2
CRL1
Bank Stmt
Date
Date
PrepareBank Rec
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Source Document Design

• Reduce the likelihood of data recording errors
• Increase the speed with whichdata can be
  recorded
• Control the work flow
• Facilitate data entry into a computer system
• Improve the use of pattern recognition devices
• Facilitate subsequent reference checking

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Form Design guidelines

• Preprint
• Titles, headings, notes, instructions
• Emphasis and Highlight
• Field order
• Caption above
• Multiple choice

• Field templates
• Combine instructions and questions
• Spacing
• Ease of keying
• Prenumbered
• Organizational standards

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Data-Entry Screen Design

• Screen organization
• Simplicity is better spacing
• Symmetry / Grouping of Items / Consistency of
  Design / Mirror Source Document
• Automatic Lookup / Combo boxes / Option Groups /
  Tab Order / Default Values / Data Filed in by
  Code /
• Error Messages / Instructions / Status Messages
• Mouse Only Operation
• Key only operation

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Data-Entry Screen Design Caption Design

• Choices include Structure, Size, Type, Font,
  Display Intensity, Format, Alignment,
  Justification, Special Effects (flat, etched,
  indented, shadow etc) and Spacing
• Spell out if direct entry Abbreviate if source
  document is used
• Display intensity higher for captions Lower
  for data entry
• Caption before data, followed by a colon right
  justified, or above if multiple - line entry
• 5 spaces between columns - Cluster in groups of 5
  or less

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Data-Entry Field Design

• Contrasting color background, cursor emphasis or
  outline box
• Radios buttons, check boxes, list boxes, option
  groups and spin boxes limit choices connected
  to query to provide a list of legal choices

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Data-Entry Field Design

• Conditional formatting
• Tabbing and skipping require manual operation

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Data Entry Form Design - Color

• Use color sparingly and consistently
• Use only a few colors that are widely spaced
  along the visual spectrum
• Use colors that are visible in the environment
• Avoid overuse of bright colors
• Use colors consistent with meaning
• Accommodate color blind users
• Take into account cultural differences

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Data Entry Form Design

• Response time
• Display rate
• Use code for validation and for automatic fill
• Auto lookup form query joined to form fills in
  information once the foreign key is selected

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Interactive Media - Senses
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Prompting and Help Facilities
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Prompting and Help Facilities
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Secondary Window Design
Use the appropriate control Controls are
typically optimized for certain types of
functions. The wrong control not only affects the
user's efficiency, but also confuses the user
about the purpose of your design.
Use appropriate labeling Always use the
appropriate capitalization and access key
assignments. Include colons when you use static
text to label another control. This not only
identifies the text as a label, but also provides
a cue for screen-reader utilities.
Appropriate sizing, spacing, and margins For
example, the recommended spacing between controls
is seven dialog units (DLUs). The recommended
size for buttons is 50 x 14 DLUs, except where a
button must be larger to accommodate its text
label. Also make good use of your overall space.
These guidelines are for the minimum space
recommendations. Avoid cramming too many controls
together if you have additional space.

• You can improve the usability of your
  application's secondary windows by observing the
  following general guidelines
• Use the appropriate control.
• Use recommended layout conventions.
• Use appropriate labeling.
• Use appropriate alignment.
• Use appropriate sizing, spacing, and margins.

Use recommended layout conventions For example,
buttons such as OK and Cancel or Yes and No
should be aligned either at the top right or
bottom right of the dialog box. (In right-to-left
versions of Windows, this alignment can be
reversed.) OK is always the first button,
followed by Cancel, and then any other buttons.
If you don't have an OK button, then Cancel
follows all the other buttons. Because OK and
Cancel are generally mapped to the ENTER and ESC
keys respectively, access key assignments are
unnecessary.

• Use appropriate alignment.
• Alignment affects readability and therefore
  usability and efficiency. It also affects the
  user's overall impression of the quality of your
  application. For example, make sure you align the
  baselines of text labels for text boxes.

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User-Centered Design Principles

• User in Control - user should always feel in
  control of the software rather than feeling
  controlled by the software.
• Directness - Design your software so that users
  can directly manipulate software representations
  of information.
• Consistency - Consistency allows users to
  transfer existing knowledge to new tasks, learn
  new things more quickly, and focus more attention
  on tasks.
• Forgiveness - An effective interface allows for
  interactive discovery. It provides only
  appropriate sets of choices and warns users about
  potential situations
• Feedback - Good feedback helps confirm that the
  software is responding to input and communicates
  details that distinguish the nature of the action
• Aesthetics - Provide a coherent environment that
  clearly contributes to the users understanding
  of the information presented.
• Simplicity - An interface should be simple (not
  simplistic), easy to learn, and easy to use. It
  must also provide access to all functionality of
  an application. Progressive disclosure

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Composition and Organization

• We choose what we read and how we think about
  information by its appearance and organization.
  We read a screen in the same way we read other
  forms of information.
• Hierarchy of information
• Focus and emphasis
• Structure and balance
• Relationship of elements
• Readability and flow
• Unity of integration

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Hierarchy of Information

• Which information is most important to the user?
• What are the user's priorities when your
  application is started?
• What does the user want or need to do first,
  second, third, and so on?
• Will the order of information support or hamper
  the user's progression through the interface?
• What should the user see on the screen first,
  second, third, and so on?

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Data Code Controls

• Unique identifiers and more compact than textual
  descriptors
• Data Coding Errors
• Addition 87942 coded as 879142
• Truncation 87942 coded as 8792
• Transcription 87942 coded as 81942
• Transposition 87942 coded as 78942
• Double transposition 87942 coded as 84972

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Factors - Frequency of Coding Errors

• 1. Length of code Longer codes are more error
  prone
• 2. Alphabetic/Numeric mix Grouping like is
  better
• 3. Choice of characters Avoid B, I, O,
  S,V ,Z Similar
  to 8, 1, 0, 5, U, 2
• 4. Mix of upper/lower case Avoid use of shift key
• 5. Predictability of charactersequence THE is
  more predictable than ZXQ

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Objectives of Coding Systems

• Flexibility Easy addition of new items or
  categories
• Meaningfulness Indicate values of
  attributes
• Compactness Maximum information in minimum
  of characters
• Convenience Easy to encode, decode
  and key
• Evolvability Adaptable to user

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Serial Codes

• Autonumber field in Access
• Assigns numbers based on a sequence
• Flexible
• No preconception of sequence useful to the user
• Reassignment of Codes?
• Difficult to remember

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Block Sequence Codes

• Blocks are assigned to groups of entities
• For example, each block could represent a
  different amount of discount to a customer
• Gives some mnemonic value to the code
• Size of the block?
• Long codes are more difficult to remember
• Wasted numbers vs. overflow

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Hierarchical Codes

• C65 / 423 / 3956Division Department
  Expenditure type
• More meaningful
• Not always concise
• Recall difficult
• May mix alpha/numerics
• Change is difficult

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Association Codes

• Attributes are selected and unique codes are
  assigned to each possible value of each attribute
• Overall code is concatenation
• Order in Combined code does not imply hierarchy

SHM32DRCOT SH shirt M Male 32 neck
size cm. DR Dress shirt COT Cotton
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Nature of check digits

• A check digit is a redundant digit(s) added to a
  code that enables the accuracy of other
  characters in the code to be checked.
• Can be a prefix or suffix or in the middle
• Program recalculates the check digit and compares
• If different the code is most likely in error

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Calculating Check Digits

• Add digits and drop tens2148 CD 2148 15
  CODE is 21485misses transpositions
• Weight digits, multiple by digits and sum
  products8 x 2 4 x 3 1 x 4 2 x 5
  42Divide by a modulus and subtract the remainder
  from the modulus42 / 11 3 with remainder of 9
  11- 9 2Final Code is 21482
• Recalculate giving check digit a weight of 1 44
• Divide by modulus 11 If remainder is 0 then Prob
  OK

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Code
Function CheckDigit(ISBN As String) As
Integer Dim Total As Long Dim CheckString As
String Dim Remainder As Long Dim ISBNShort As
String Dim DigitNumber As Integer Dim ISBNCheck
As String For DigitNumber 1 To Len(ISBN) - 1
If Mid(ISBN, DigitNumber, 1) ltgt "-" Then
ISBNShort ISBNShort Mid(ISBN, DigitNumber,
1) Else End If Next DigitNumber
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For DigitNumber 1 To Len(ISBNShort) Total
Total DigitNumber CLng(Mid(ISBNShort,
DigitNumber, 1)) Next DigitNumber Remainder
Total Mod 11 If Remainder 10 Then
CheckString "X" Else CheckString
Str(Remainder) End If If Right(ISBN, 1) "X"
Then ISBNCheck "X" Else ISBNCheck
Str(Right(ISBN, 1)) End If
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If CheckString ISBNCheck Then CheckDigit
True Else CheckDigit False End If End
Function
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Efficiency of Different Moduli for Check Digits
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Batch Controls

• Types of batches
• Means of batch control
• Financial totals
• Hash totals
• Document/record counts
• Design of Batches
• small to find errors, large enough unit of work,
  logical unit

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Validation of Data Input- field checks

• Missing data/ blanks Required Property
• Alphabetics/numerics Data Type Property
• Range Between 5 and 10 Validation Rule
• Set membership In(NS,NB,PEI) Validation Rule
• Check digit CheckDigit(Me!ISBN) Validation Rule
• Master reference Lookup Field Type
• Size Size Property
• Format mask Input Mask

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Validation of Data Input - Record checks

• Reasonableness - Value of one field depends upon
  the value in another field in the same record.
  Filtering combo boxes based on selected item.
  AfterUpdate Event Filling in data with code.
  Dlookup()
• Valid sign-numerics - Value of one field
  determines valid sign for another field see Yes
  I Can
• Size- Variable length records
• Sequence checks logical record consists of more
  than one physical record.

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Data Entry Techniques

• Using Variables to Refer to Object Names
• Keeping Two Forms Synchronized
• Assigning Values to Controls and Properties at
  Run Time
• Disabling a Command Button at Run Time
• Using Pop-up Forms and Dialog Boxes
• Creating a Pop-up Form to Display Details About
  an Item in a Subform
• Using a Custom Dialog Box to Collect Information
• Using a Message Box to Display a Message
• Filtering and Sorting Data in Forms and Reports
• Populating Controls on a Form
• Adding a Row to a Combo Box List
• Using the Tab Control to Organize Forms

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Creating a Pop-up Form to Display Details About
an Item in a Subform
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Validation of Data Input - Batch Checks

• Control Totals Does the accumulation of a field
  across all records in a batch or the number of
  records in the batch reconcile with the number
  specified for the batch? Use Total query to check
  results.
• Transaction Type All input records in a batch
  might have to be of a particular type.
  Specialized forms
• Batch Serial Number All input records in a
  batch might have to include a serial number that
  has been assigned to the batch
• Sequence check the input records in a batch
  might have to follow a particular order.

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Validation of Data Input - File checks

• Internal label the input validation program
  checks to see that it is accessing a file having
  the correct name
• Generation number the input validation program
  checks to see that it is accessing the correct
  generation of any file it uses.
• Retention date The input validation program
  checks to see that it is not using a file whose
  retention date has expired.
• Control totals Control totals can be calculated
  for a file on the basis of the contents of the
  file. The input validation program checks to see
  that it is using a file with the correct control
  totals.

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Reporting of Data Input Errors

• Data validation text property
• Message boxes
• Automatic action form opening, add to list,
  transaction rollback, retry on record lock
• Context help
• Microsoft predefined error codes error file
• Referential integrity
• Prevent saving if incomplete record edit undo
• Creating suspense or error files append and
  delete record action queries.

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Instruction Input

• Menu driven languages
• Question - Answer dialogs
• Command languages
• Forms based languages
• Natural languages
• Direct manipulation languages

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Validation of Instruction Input

• Lexical validation
• Syntactic validation
• Semantic validation

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Audit Trail Controls

• Identity of source person
• Identity of data entry person
• Time/Date
• Physical device identifier
• Account or record updated
• Standing data effected
• Details of the transaction
• Batch numbers