Chapter 2 discusses conducting an information systems audit, focusing on the complexities and risks auditors face while evaluating data processing systems in various organizational contexts. It covers the importance of internal controls, the audit risk model, types of audit procedures, and the methodologies for auditing through or around the computer. The document emphasizes the structured approach auditors must take to ensure data integrity, asset safeguarding, and system effectiveness.

1. Chapter 2
Conducting an Information
Systems Audit
Sreekanth N
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2. Contents
• Introduction
• The big Question
• Learning objectives
• Nature of controls
• Dealing with complexity
• Audit Risks
• Types of Audit Procedures
• Overview of Steps in an Audit
• Auditing Around or Through the computer.
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3. Introduction
• Auditors can perform a detailed audit in small organizations.
• All organizations are of not the same size.
• Auditing in big organizations are difficult.
• Detailed check on data process inside IS systems become complex.
• Auditors resort to sampling.
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4. The big question?
• How can an auditor perform IS audit so that they obtain reasonable
assurance that an organization safeguards its data-processing assets,
maintains data integrity, and achieve system effectiveness and
efficiency ?
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5. Learning Objectives
• Learn the general approach followed for information systems audit.
• Learn the nature of controls.
• Learn techniques for simplifying complexity encountered while
making evaluation judgements or computer-based information
systems.
• Learn the basic risks auditors face and the type of audit procedures
used to control and asses these risks.
• Finally we examine a major decision auditors must make while doing
an IS audit.
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6. Attestation vs Audit
• Attestation: An attestation is a type of engagement in which an attester
(auditor,practitioner,accountant) provides a report as to whether an
assertion (made by an asserter management) has been prepared in
conformity with the appropriate criteria.
• Attestations include financial statement audits, reporting on forecasts, projections,
pro-forma information, effectiveness of internal control etc.
• Attestation Standards apply only to situations not addressed by other professional
standards.
• Audit: An audit is a type of attest function in which an auditor provides an
independent opinion (positive assurance) about whether management
(asserter) has prepared financial statements in conformity with an
applicable financial reporting framework (criteria).
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7. Nature of controls
• A control is a system that prevents, detects, or correct unlawful
events.
• System – Set of interrelated components working together to achieve
some overall purpose
• Unlawful event- Arises if unauthorized, in accurate, incomplete,
redundant, ineffective, or inefficient input enters the system.
• Preventive control
• Detective control
• Corrective control
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8. Dealing with Complexity
• Conducting an IS audit is an exercise in dealing with complexity.
• Because complexity is the root cause of problems face by many
professionals two guidelines have been developed in IS audit.
1. Given the purpose of IS audit, factor the system to be evaluated
into subsystems.
2. Determine the reliability of each subsystem and implications of
each subsystems level of reliability for the overall reliability of the
system.
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9. Dealing with Complexity –> Subsystem
Factoring
• Subsystem performs basic function and are logical components
• Factoring – Decomposing a system into subsystems (iterative process)
• Systems theory gives two guidelines to identify and delineate
subsystems
• should be relatively independent
• should be internally cohesive
• Auditors have recognized some systems cannot be audited based on
these.
• Over time two methodologies were developed to factor systems.
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10. Dealing with Complexity –> Subsystem
Factoring
IS Function
Application
subsystems
Application
systems
Cycles
Management
subsystems
Management
systems
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11. Dealing with Complexity –> Subsystem
Factoring –> Management subsystems
• Based on managerial functions that must be performed to ensure
that development, implementation, operation and maintenance of IS
proceed in planned and controlled manner.
• Managerial systems function to provide a stable infrastructure in
which information systems can be built, operated and maintained on
a day to day basis.
• Some of the management subsystems are : Top management, IS
management, Systems development management, Programming
management, Data administration, Quality assurance, Security
administration, Operations management
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12. Dealing with Complexity –> Subsystem
Factoring –> Application Subsystems
• Based of cycles approach.
• IS systems are grouped into cycles.
• Examples of cycles : Sales and collection, payroll and personnel, acquisition
and payments, inventory etc.
• Each cycle is then factored into application subsystems.
• Application systems into application subsystems.
• Application Subsystems can includes Boundary, Input,
Communication, Processing, Database, Output
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13. Dealing with Complexity –> Subsystem
Factoring –> Assessing Subsystem Reliability
• Beginning with the lowest-level subsystems, all the different types of
lawful and unlawful events that can occur to the system are
identified.
• Primary concern are unlawful events.
• To identify we focus on the major functions each subsystem performs.
• As a basis we focus on (walk-through technique)
• the transactions that can occur as an input to the subsystem as all events
arise from a transaction.
• How the subsystem processes this transaction and understand each
processing step.
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14. Dealing with Complexity –> Subsystem
Factoring –> Assessing Subsystem Reliability
• Costly to trace each transaction.
• Auditors focus on classes.
• Group similar transactions into classes and analyze it.
• When events are identified auditors evaluate if controls are in place.
• They collect evidence on the controls and see if the losses are
reduced to acceptable levels.
• Errors made at one level can propagate to higher levels
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15. Audit Risks
• Systems auditors are concerned with four objectives:
• Asset safeguarding
• Data integrity
• System effectiveness
• System efficiency
• Auditors are concerned with whether errors or irregularities cause
material losses or material misstatements in the financial information
• Because of test nature of auditing, auditors might fail to detect real or
potential material losses and account misstatements.
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16. Audit Risks
• The risk of an auditor failing to detect actual or potential material losses or account
misstatements at the conclusion of the audit is called the audit risk.
• Auditors choose an audit approach and design audit procedures in an attempt to reduce
this risk to a level deemed acceptable.
• For determining desired audit risk following audit risk model is adopted :
DAR = IR x CR x DR
• DAR is the desired audit risk
• IR is the inherent risk, likelihood that a material loss or account misstatement exists in
some segment of the audit before the reliability of internal controls is considered.
• CR is the control risk, likelihood that internal controls in some segment of the audit will
not prevent, detect, or correct material losses or account misstatements that arise.
• DR is the detection risk, the audit procedures used in some segment Of the audit will fail
to detect material losses or account misstatements.
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17. Audit Risks
• To apply the model, auditors first choose their level of desired audit risk.
• Auditors consider such factors as the level of reliance external parties are likely to
place on the financial statements, the likelihood of the organization encountering
financial difficulties subsequent to the audit, they assess the short- and long-run
consequences for their organizations if they fail to detect real or potential
material losses from ineffective or inefficient operations.
• Next auditors consider the level of inherent risk. Initially auditors consider
general factors such as
• the nature of the organization,
• the industry in which it operates,
• the characteristics of management, and accounting and auditing concerns.
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18. Audit Risks
Inherent Risk in Financial System
• Those that usually provide financial control over the major
assets of an organization :
• cash receipts and disbursements,
• payroll,
• accounts receivable and payable—often have higher inherent risk.
• Because they are frequently the target of fraud.
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19. Audit Risks
• To assess the level of control risk associated with a segment of the audit, auditors
consider the reliability of both management and application controls.
• Auditors usually identify and evaluate controls in management subsystems first.
• Management (subsystem) controls are fundamental controls because they cover
all application systems.
• Thus, the absence of a management control is a serious concern for auditors.
• Next auditors calculate the level of detection risk they must attain to achieve
their desired audit risk. They then design evidence collection procedures in an
attempt to achieve this level of detection risk.
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20. Audit Risks
• The whole point in considering the audit risk model is that audit efforts should be
focused where they will have the highest payoffs.
• In most cases auditors cannot collect evidence to the extent they would like.
• Accordingly, they must be judicious in terms of where they apply their audit
procedures and how they interpret the evidence they collect.
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21. Types of Audit Procedures
When external auditors gather evidence to determine whether material losses have
occurred or financial information has been materially misstated, they use five types
Of procedures:
• Procedures to obtain an understanding of controls: Inquiries, inspections, and
observations can be used to gain an understanding Of what controls supposedly
exist, how well they have been designed, and whether they have been placed in
operation.
• Tests of controls: Inquiries, inspections, observations, and performance of control
procedures can be used to evaluate whether controls are operating effectively.
• Substantive tests of details of transactions: These tests are designed to detect
dollar errors or irregularities in transactions that would affect the financial
statements.
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22. Types of Audit Procedures
• Substantive tests of details of account balances: These tests focus on the ending
general ledger balances in the balance sheet and income statement.
• Analytical review procedures: These tests focus on relationships among data
items with the objective of identifying areas that require further audit work.
• Auditors usually carry out the less costly audit procedures first in the hope the
evidence obtained from these procedures indicates it is unlikely a material loss or
material misstatement has occurred or will occur. If this outcome arises, auditors
can alter the nature, timing, and extent of the more costly tests used.
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23. Overview of Steps in an Audit
Start
Stop
Obtain
Understanding
Of control structure
Assess control
risk
Preliminary
Audit work
Reassess
Control risk
Tests of
controls
Limited
Substantive
testing
Extended
Substantive
testing
Form audit
Opinion and
Issue report
Rely on
Controls ?
Increase
Reliance on
Controls ?
Still
Rely on
Control ?
no
Yes
no
yes
no
yes
Major Steps
to be
undertaken
in an audit
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24. Overview of Steps in an Audit – Planning audit
• Planning is the first phase of an audit.
• For External auditor - investigating new and continuing clients to
determine whether the audit engagement should be accepted,
assigning appropriate staff to the audit, obtaining an engagement
letter, obtaining background information on the client, understanding
the client's legal obligations, and undertaking analytical review
procedures to understand the client's business better and identify
areas of risk in the audit
• For an internal auditor -understanding the objectives to be
accomplished in the audit, obtaining background information,
assigning appropriate staff, and identifying areas of risk.
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25. Overview of Steps in an Audit – Planning audit
• Judgment on the level of control risk associated with each segment of the
audit is hard.
• To decide on the level of control risk, auditors must first understand the
internal controls used within an organization. Internal controls comprise of
five interrelated components:
• Control Environment - Elements that establish the control Context in which specific
accounting systems and control procedures must operate.
• Risk Assessment - Elements that identify and analyze the risks faced by an
Organization and the ways these risks can be managed.
• Control Activities - Elements that operate to ensure transactions are authorized,
duties are segregated, adequate documents and records are maintained, assets and
records are safeguarded, and independent checks on performance and valuation of
recorded amounts occur.
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26. Overview of Steps in an Audit – Planning audit
• Judgment on the level of control risk associated with each segment of
the audit is hard.
• To decide on the level of control risk, auditors must first understand
the internal controls used within an organization. Internal controls
comprise of five interrelated components:
• Information and Communication-Elements in which information is identified,
captured, and exchanged in a timely and appropriate form to allow personnel
to discharge their responsibilities properly.
• Monitoring- Elements that ensure internal controls operate reliably over time.
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27. Overview of Steps in an Audit – Planning audit
• After auditors obtain an understanding of the internal controls, they
then must determine the control risk in relation to each assertion:
• If auditors assess control risk at less than the maximum level, they must then
identify the material controls that relate to the assertion and test the controls
to evaluate whether they are operating effectively.
• If auditors assess control risk at the maximum level, they do not test controls;
they might conclude that internal controls are unlikely to be effective and
therefore cannot be relied upon or that a more effective and efficient audit
can be conducted using a substantive approach.
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28. Overview of Steps in an Audit – Tests of
Controls
• Auditors test controls when they assess the control risk for an assertion at less
than the maximum level.
• They rely on controls as a basis for reducing more costly testing.
• Tests of controls evaluate whether specific, material controls are reliable.
• This phase usually begins by again focusing first on management controls.
• If testing shows that, contrary to expectations, management controls are not
operating reliably, there might be little point to testing application controls.
• If auditors identify serious management-control weaknesses, they might have to
issue an adverse opinion or undertake substantive tests of transactions and
balances or overall results.
• Auditors conduct the evaluation iteratively for each management subsystem and
each application subsystem that is important.
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29. Overview of Steps in an Audit – Tests of
Controls
• If auditors conclude that management controls are in place and
working satisfactorily, they then would evaluate the reliability of
application controls.
• For each transaction considered, auditors evaluate whether the
control is operating effectively.
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30. Overview of Steps in an Audit – Tests of
Controls
• After auditors have completed tests of controls, they again assess
control risk.
• After the test results, auditors might conclude that internal controls
are stronger or weaker than initially anticipated.
• They might also conclude that it is worthwhile to perform more tests
of controls with a view to further reducing the further testing.
• Accordingly, auditors conclude control risk has decreased and seek
further evidence to support this assessment.
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31. Overview of Steps in an Audit – Tests of
Transactions
• Auditors use tests of transactions to evaluate whether erroneous or
irregular processing of a transaction has led to a material misstatement of
financial information.
• Typical attest tests of transactions include
• tracing journal entries to their source documents,
• examining price files for propriety, and
• testing computational accuracy.
• Ex : Auditors usually use generalized audit software to check whether the
interest paid on bank accounts has been calculated correctly.
• From an operational perspective, auditors use tests of transactions to
evaluate whether transactions or events have been handled effectively and
efficiently.
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32. Overview of Steps in an Audit – Tests of
Transactions
• In an attest audit, auditors conduct tests of transactions at interim
dates in order to reduce the amount of substantive tests of balances
to be done at financial year end and thus to reduce the overall costs
of the audit.
• In an operational audit for effectiveness and efficiency purposes,
auditors also use tests of transactions at interim dates in order to
reduce the amount of substantive testing of overall results to be done
near the reporting date.
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33. Overview of Steps in an Audit – Tests of
Transactions
• If the results of tests of transactions indicate that material losses have
occurred or might occur or that financial information is or might be
materially misstated, substantive tests of balances or overall results
will be expanded.
• Auditors can use expanded tests of balances or overall results to
obtain a better estimate of the losses or misstatements that have
occurred or might occur.
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34. Overview of Steps in an Audit – Tests of
Balances or Overall Result
• Auditors conduct tests of balances or overall results to obtain
sufficient evidence for making a final judgment on the extent of losses
or account misstatements that occur when
• the information systems function fails to safeguard assets,
• maintain data integrity,
• achieve system effectiveness and efficiency.
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35. Overview of Steps in an Audit – Completion of
the Audit
• In the final phase of the audit, external auditors undertake several
additional tests to bring the collection of evidence to a close.
• They must then formulate an opinion about whether material losses or
account misstatements have occurred and issue a report.
• The professional standards in many countries require one of four types of
opinion be issued:
• Disclaimer of opinion: On the basis of the audit work conducted, the auditor is
unable to reach an opinion.
• Adverse opinion: The auditor concludes that material losses have occurred or that
the financial statements are materially misstated.
• Qualified opinion: The auditor concludes that losses have occurred or that the
financial statements are misstated but that the amounts are not material.
• Unqualified opinion: The auditor believes that no material losses or account
misstatements have occurred.
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36. Auditing Around or Through the Computer
• When auditors come to the controls testing phase of an information
systems audit, one of the major decisions they must make is whether to
test controls by auditing around or through the computer.
• The phrases "auditing around the computer" and "auditing through the
computer" are carryovers from the past.
• Debate on how much technical knowledge was required to audit computer
systems. Two methods were formulated:
• Auditors could evaluate computer systems simply by checking their input and output.
• Internal workings of computer systems were examined and evaluated.
• Both has its own merits and demerits and both are considered now for
auditing.
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37. Around the Computer
• Auditing around the computer involves arriving at an audit opinion
through examining and evaluating management controls and then
input and output only for application systems.
• Based on the quality of an application system's input and output,
auditors infer the quality of the application system's processing.
• The application system's processing is not examined directly. Instead,
auditors view the computer as a black box.
• Cost effective way if the SW used is one package.
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38. Around the Computer
• Auditors seek to ensure
• the organization has not modified the package in any way,
• adequate controls exist over the source code, object code, and
documentation to prevent unauthorized modification of the package
• high-quality controls exist over input to and output from the package.
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39. Through the Computer
• The Advantage of auditing through the computer is that auditors have
increased power to test an application system effectively.
• Increase their confidence in the reliability of the evidence collection
and evaluation.
• By directly examining the processing logic embedded within an
application system auditors are better able to assess the system's
ability to cope with change and the likelihood of losses or account
misstatements arising in the future.
• The approach has two disadvantages.
• it can sometimes be costly
• extensive technical expertise to understand how the system works
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40. Through the Computer
• They use the computer to test
• the processing logic and controls existing within the system
• the records produced by the system.
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41. Thank You
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