Computerised Accounting System (CAS) | ISC Class 11 Accounts Notes

This note covers the Computerised Accounting System (CAS): what it is, its components, its salient features, its advantages and limitations compared with manual accounting, and the Accounting Information System (AIS) that it supports.

What is a Computerised Accounting System (CAS)?

A Computerised Accounting System is a system of accounting in which a computer and accounting software are used to record, classify, summarise and report financial transactions, in place of writing them by hand in books of account.

The underlying accounting principles, concepts and conventions remain the same as in manual accounting; only the mode of recording and processing changes from paper to an electronic medium.

In CAS, a transaction is entered once into the computer through a voucher (a document recording the details of a transaction, such as date, accounts affected and amount), and the software automatically posts the entry to the relevant ledger accounts and generates reports such as the trial balance, trading and profit and loss account, and balance sheet.

This is possible because the software works on the double-entry principle in the background, so a single data entry updates every account that the transaction affects.

CAS is widely used by businesses of every size, from a small shop using a simple accounting package to a large company using an enterprise-level system, because it reduces the time and effort needed to prepare accounts and reduces the chance of clerical errors such as wrong totalling or posting to the wrong account.

In India, popular ready-made accounting packages such as Tally, Busy and Marg ERP are commonly used by traders and small companies for day-to-day bookkeeping. Many Indian businesses have also adopted CAS because it makes it easier to generate the invoices, returns and reports that Indian GST compliance requires, since the software can produce GST-wise summaries directly from the vouchers already entered for accounting purposes, instead of preparing these figures separately by hand.

What are the components of CAS?

A Computerised Accounting System is built from several components that work together. Each component performs a distinct role, and the system cannot function properly if any one of them is missing or faulty.

The five building blocks

These five components are sometimes remembered together as the building blocks of any computer-based system, not just an accounting one: without hardware there is nothing to run the software on, without software the hardware cannot process accounting data, without trained people the system cannot be operated correctly, without a clear procedure different operators may work inconsistently, and without accurate data even the best hardware and software will produce wrong reports.

Front-end, back-end and internal control

Within the software component, accounting packages generally provide a front-end interface (the screens and menus through which the operator enters vouchers and views reports) and a back-end database (where the entered data is actually stored and from which reports are generated).

A good CAS also includes an internal control feature, meaning built-in checks such as passwords and access levels, so that only authorised persons can enter or alter data.

What are the salient features of CAS?

CAS has certain features that distinguish it from manual bookkeeping and explain why organisations prefer it.

Accuracy, speed and reliability

1. Simple and integrated: a single data entry in a voucher updates every related ledger account and report automatically, so the system behaves as one integrated whole rather than separate books.
2. Accuracy: because the arithmetic and posting are done by the software rather than by hand, the chance of errors such as wrong casting or wrong carrying forward is greatly reduced.
3. Speed: large volumes of transactions can be processed and reports generated in far less time than would be needed to write and total them by hand.
4. Reliability: the computer carries out the same processing rules every time, so the output can be trusted to be consistent as long as the data entered is correct.

Real-time information, scalability and MIS reports

1. Real-time information: as soon as a voucher is entered, reports such as the trial balance are updated immediately, so management always sees the current position rather than a position that is out of date.
2. Scalability: a computerised system can usually handle a growing volume of transactions and users as a business expands, without a complete change of system.
3. MIS reports: the system can produce a wide range of management information system (MIS) reports, such as outstanding receivables or stock summaries, that would be time-consuming to prepare by hand.
4. Networking: many systems can be connected across branches or departments, so that data entered at one location is accessible at another.

Together these features mean that CAS is designed to support accurate, fast and up-to-date accounting rather than merely to replace a paper ledger with a screen.

What are the advantages (merits) of CAS?

Computerisation gives several benefits over manual accounting, which is why most organisations beyond a very small scale have adopted it.

Advantages in processing work

• Speed and accuracy: transactions are processed and reports prepared much faster, and with fewer clerical errors, than when done by hand.
• Reliability of output: the same rules are applied consistently to every transaction, so figures can be relied upon once the data entered is correct.
• Up-to-date information: management can obtain the latest financial position at any time, rather than waiting for books to be totalled at the end of a period.
• Scalability: the system can cope with a growing number of transactions as the business grows, without redesigning the whole accounting process.

Advantages in storage and staff use

• Legibility: printed reports are always clear and readable, unlike handwritten entries that may be difficult to read.
• Efficient storage and retrieval: large amounts of data can be stored compactly and old records can be searched for and retrieved quickly, instead of searching through bulky manual registers.
• Quality of work and motivation: staff are freed from repetitive manual totalling and can spend more time on analysis, which can improve the quality and interest of their work.

Taken together, these advantages explain why a growing business usually finds that the benefits of speed, accuracy and timely reporting outweigh the cost of setting up a Computerised Accounting System once its volume of transactions rises beyond what a few clerks can handle by hand.

What are the limitations (disadvantages) of CAS?

CAS also has drawbacks, and these must be weighed against its advantages before a business decides to adopt or expand it.

Cost and human factors

• Cost of installation and training: buying suitable hardware and software, and training staff to use them properly, can be expensive, particularly for a small business.
• Staff resistance: employees who are used to manual methods may resist the change, fearing that computerisation will reduce their job security.
• Disruption during changeover: shifting from a manual to a computerised system can disrupt normal work until staff become familiar with the new procedures.

Technical and security risks

• System and power failure: a breakdown of hardware, software or the electricity supply can bring accounting work to a halt until the fault is fixed.
• Risk to data security: data stored electronically can be lost through a virus, hacking or accidental deletion if proper back-up and security measures are not in place.
• Inability to check unanticipated errors: the software applies only the checks it was programmed with, so it cannot catch a mistake a person would notice by judgement, such as a voucher entered in the wrong account.
• Possible health effects: prolonged use of computer screens can cause eye strain and other health problems for operators if proper working conditions are not followed.

Because of these limitations, a business adopting CAS needs to plan for staff training, regular data back-up, a reliable power supply (often with a stand-by arrangement) and proper access controls, so that the advantages of speed and accuracy are not undermined by these risks.

What is an Accounting Information System (AIS)?

An Accounting Information System (AIS) is the wider system within which a Computerised Accounting System operates.

Scope of AIS

It is the combination of people, procedures, data, software and information technology infrastructure that an organisation uses to collect, record, store and process accounting data, and to turn that data into financial information for decision-makers.

While CAS refers specifically to the computer-based recording and processing of transactions, AIS is a broader concept: it covers how data flows into the system from source documents, how it is processed and stored, how internal controls check it for accuracy and authorisation, and how the resulting reports reach the people who need them, both inside the organisation (such as managers) and outside it (such as investors, lenders and tax authorities).

Components of AIS

The components of an AIS are similar to those of CAS, namely people, procedures and instructions, data, software, and IT infrastructure, together with internal controls that safeguard the data at every stage.

A well-designed AIS ensures that the accounting information produced is accurate, timely and secure, and that it reaches the right user in a form that is useful for decision-making.

How does CAS compare with manual accounting?

Comparing the two systems side by side helps to bring out why organisations move from manual books to a computerised system as their volume of transactions grows.

Comparison table

This comparison shows that manual accounting may still suit a very small business with few transactions, while CAS becomes increasingly worthwhile as the number of transactions, the need for quick reports and the size of the organisation grow.

Worked examples

Worked example 1. A trader employs one clerk at a salary of ₹8,000 a month to write up her manual books, taking about 20 days of work each month.

A ready-made accounting package (such as Tally, a widely used Indian accounting software) costs ₹25,000 to buy and install, plus ₹1,000 a month for support, and would let the same clerk finish the posting in far fewer hours.

Should she switch to CAS, and would two months of the clerk's salary cover the one-time software cost?

Answer: Two months of the clerk's salary = 2 × ₹8,000 = ₹16,000, which is less than the ₹25,000 one-time cost of the software, so the software is not recovered from two months' salary alone; it needs more months of saved time and reduced errors to justify the ₹25,000 plus ₹1,000 a month running cost.

Since the trader's transaction volume is rising and manual posting already takes most of the clerk's working days, she should move to the computerised accounting system, as the speed and accuracy gained will repay the ₹25,000 cost over a reasonable period while freeing the clerk for other work.

Worked example 2. An accountant is choosing between a ready-made accounting package priced at ₹20,000 and a tailor-made package priced at ₹1,20,000, built specially for the firm's unusual reporting requirements.

The ready-made package meets 90% of the firm's standard needs; the tailor-made package meets all of them but costs ₹1,00,000 more.

Answer: The extra cost of the tailor-made package over the ready-made one is ₹1,20,000 − ₹20,000 = ₹1,00,000.

A ready-made package is cheaper, quicker to install and is supported by many trained users, which suits a firm whose requirements are fairly standard.

A tailor-made package is justified only when the firm's reporting needs are genuinely unusual and the extra ₹1,00,000 and longer installation time can be absorbed.

If the firm's needs are mostly standard, it should choose the ready-made package; it should choose the tailor-made option only if the special reports are essential to the business.

Worked example 3. A company's accounting staff are reluctant to switch from manual ledgers to a computerised system, fearing it will threaten their jobs, even though management expects the system to save ₹30,000 a month in overtime payments currently made for late totalling of books.

Answer: Staff resistance is a known limitation of computerisation, but it can be managed rather than treated as a reason to avoid CAS altogether.

The ₹30,000 a month saved in overtime shows a clear financial benefit to the firm from faster posting.

Management should explain that computerisation is meant to remove repetitive manual work, not staff, and should provide proper training so employees can move into analysis and reporting tasks.

The firm should proceed with computerisation in a phased manner, alongside training, rather than abandon the plan because of initial resistance.

Worked example 4. A business operates in an area with frequent power cuts and is worried that a computerised accounting system will stop working during outages.

A stand-by power back-up unit costs ₹15,000 to install and ₹500 a month to maintain, compared with an estimated loss of ₹2,000 in re-work every time unsaved data is lost during a power cut.

Answer: Power failure is a genuine limitation of any computerised system, since processing and data entry cannot continue without electricity.

If data loss from a power cut occurred even eight times a year, the re-work cost would be 8 × ₹2,000 = ₹16,000, which already exceeds the one-time ₹15,000 cost of the back-up unit.

The business should recommend installing the ₹15,000 back-up power supply alongside regular saving and back-up of data, rather than rejecting computerisation on this ground alone.

Going beyond the syllabus

Modern accounting software often goes further than basic recording by linking accounting data with other business functions, such as inventory, payroll and billing, in a single integrated package, so that a sale recorded once automatically updates stock records and customer accounts as well as the books of account.

Many organisations also keep their data on remote servers accessed over the internet, which allows authorised staff to view accounts from more than one location while central back-ups are kept to guard against loss of data.

Why data back-up matters

Because electronic records can be damaged or lost through a virus, hardware fault or accidental deletion, most firms keep more than one copy of their accounting data, often in more than one physical location, so that work already entered is not lost if one copy is damaged.

A regular back-up routine, combined with password-protected access, is therefore treated as a basic discipline in any computerised accounting environment, not an optional extra.

Glossary

• Computerised Accounting System (CAS) — a system that uses a computer and accounting software to record, classify, summarise and report financial transactions.
• Accounting Information System (AIS) — the wider combination of people, procedures, data, software and IT infrastructure used to produce accounting information for decision-making.
• Hardware — the physical equipment used to operate a computerised system, such as the computer, printer and scanner.
• Software — the programs, including the operating system and the accounting application, that instruct the hardware what to do.
• Voucher — a document recording the details of a transaction, such as date, accounts affected and amount, used as the basis for data entry.
• Front-end interface — the screens and menus through which an operator enters data and views reports in an accounting package.
• Back-end database — the part of the software where entered accounting data is actually stored and from which reports are generated.
• Internal control — built-in checks, such as passwords and access levels, that ensure only authorised persons can enter or alter data.
• MIS reports — management information system reports generated from accounting data to assist managerial decisions.
• Networking — connecting computers across branches or departments so that data entered at one point is accessible elsewhere.
• Data security — measures taken to protect accounting data from loss, damage or unauthorised access.
• Back-up — a stored copy of data kept separately so that it can be restored if the original data is lost or damaged.
• Scalability — the ability of a system to continue handling work efficiently as the volume of transactions or users increases.

Common errors and misconceptions

• Misconception: Computerised accounting follows different principles from manual accounting. Correct: The underlying accounting principles and concepts are the same; only the method of recording and processing changes.
• Misconception: CAS and AIS mean exactly the same thing. Correct: CAS refers to the computer-based recording and processing of transactions, while AIS is the broader system of people, procedures, data and technology that produces accounting information.
• Misconception: A computerised system removes the need for trained staff. Correct: People remain an essential component of CAS, since trained operators must enter data correctly and follow the agreed procedure.
• Misconception: Once installed, a computerised system cannot fail or lose data. Correct: Power failure, system breakdown and data loss are recognised limitations, which is why back-up and security measures are needed.
• Misconception: CAS is worthwhile only for large companies. Correct: CAS is useful for any business whose volume of transactions makes manual recording slow or error-prone, including many small businesses.
• Misconception: Manual accounting has no advantages at all. Correct: Manual accounting has a lower initial cost and may still suit a very small business with few transactions.
• Misconception: Staff resistance means computerisation should be abandoned. Correct: Resistance is a limitation that can usually be managed through training and a phased changeover rather than a reason to avoid CAS.

Exam-style questions with model answers

Q1. State what is meant by a Computerised Accounting System. [1 mark]

1. A Computerised Accounting System is a system that uses a computer and accounting software to record, classify, summarise and report financial transactions, following the same accounting principles as manual accounting.

Q2. State two salient features of CAS. [2 marks]

1. CAS is accurate, since arithmetic and posting are carried out by the software rather than by hand, reducing clerical errors.
2. CAS provides real-time information, so reports such as the trial balance are updated as soon as a voucher is entered.

Q3. Enumerate any three components of a Computerised Accounting System. [3 marks]

1. Hardware, the physical equipment such as the computer and printer used to run the system.
2. Software, the programs including the operating system and the accounting application that process the data.
3. People, the trained personnel who enter and use the accounting data under an agreed procedure.

Q4. A trader processes about 70 transactions a day by hand and finds she is often unable to finish her books on the same day. State, with one reason, whether she should adopt a Computerised Accounting System. [2 marks]

1. She should adopt a Computerised Accounting System.
2. With 70 transactions a day, manual posting is slow and prone to error, whereas CAS enters each voucher once and posts it automatically, giving speed and accuracy and allowing her to complete her books on time.

Q5. Distinguish between a Computerised Accounting System and an Accounting Information System. [3 marks]

1. A Computerised Accounting System refers specifically to the use of a computer and accounting software to record and process financial transactions.
2. An Accounting Information System is a broader system of people, procedures, data, software and IT infrastructure that collects, stores and processes accounting data to produce information for decision-makers.
3. CAS can be seen as one part of a firm's overall Accounting Information System, which also covers how data flows in from source documents and how reports reach internal and external users.

Q6. Explain three advantages of CAS over manual accounting. [3 marks]

1. Speed: large volumes of transactions can be processed and reports prepared far faster than by writing and totalling them by hand.
2. Accuracy: the computer carries out posting and totalling consistently, reducing clerical errors found in manual books.
3. Up-to-date information: because entries update reports immediately, management can see the current financial position at any time rather than waiting for periodic totalling.

Q7. Discuss four limitations of a Computerised Accounting System. [4 marks]

1. Cost of installation and training, since buying suitable hardware and software and training staff can be expensive, particularly for a small business.
2. Staff resistance, as employees used to manual methods may fear that computerisation threatens their jobs.
3. System and power failure, which can halt accounting work until the fault is corrected.
4. Risk to data security, since electronic data can be lost through a virus, hacking or accidental deletion if proper back-up and security measures are not followed.

Q8. A business is deciding whether to adopt CAS. It has 400 daily transactions, needs daily reports for three branch managers, and currently maintains manual ledgers that take two days to finalise each month. Describe the decision it should take, giving reasons based on the features, advantages and limitations of CAS. [6 marks]

1. The business should adopt a Computerised Accounting System.
2. With 400 daily transactions, manual recording is slow and increases the risk of clerical errors in posting and totalling.
3. CAS would allow a single voucher entry to update all affected ledger accounts automatically, saving considerable time each month compared with the current two-day delay in finalising books.
4. Because CAS gives real-time information, the three branch managers could receive up-to-date reports as soon as transactions are entered, rather than waiting for month-end figures.
5. Networking would allow data entered at each branch to be consolidated centrally for reporting purposes.
6. The business should, however, plan for the limitations of CAS by training staff properly, arranging a stand-by power supply, and keeping regular data back-ups, so that the advantages of speed and accuracy are not undermined by system failure or data loss.

Key takeaways

• CAS uses a computer and accounting software to record, classify, summarise and report transactions, following the same accounting principles as manual accounting.
• The components of CAS are hardware, software, people, procedure and data, each performing a distinct role.
• Salient features of CAS include accuracy, speed, reliability, real-time information, scalability and the ability to generate MIS reports.
• Advantages of CAS include speed, accuracy, reliability, up-to-date information, scalability, legibility and efficient storage and retrieval.
• Limitations of CAS include the cost of installation and training, staff resistance, disruption during changeover, system and power failure, and risk to data security.
• An Accounting Information System is the broader combination of people, procedures, data, software and IT infrastructure used to produce accounting information.
• CAS can be seen as part of a firm's overall Accounting Information System.
• The choice between manual and computerised accounting depends on the volume of transactions, the need for fast reports, and the cost the business can bear.

Test yourself

What is a voucher in the context of CAS?

A voucher is a document recording the details of a transaction, such as date, accounts affected and amount, used as the basis for data entry into the system.

Name any three components of CAS.

Any three of hardware, software, people, procedure and data are acceptable components of a Computerised Accounting System.

Why does CAS provide real-time information?

Because entering a voucher once automatically updates every related ledger account and report, so reports such as the trial balance are current as soon as entries are made.

Give one reason why a firm might still use manual accounting.

A very small firm with few transactions may find manual accounting's lower initial cost more suitable than the cost of installing and maintaining CAS.

What is the difference in scope between CAS and AIS?

CAS is the computer-based recording and processing of transactions, while AIS is the broader system of people, procedures, data, software and IT infrastructure around it.

State one health-related limitation of using computerised systems.

Prolonged use of computer screens can cause eye strain and other health problems for operators if proper working conditions are not followed.

How can a business reduce the risk of losing accounting data?

By keeping regular back-ups of its data and using proper security measures such as passwords and access controls.

Why might employees resist the introduction of CAS?

Employees used to manual methods may fear that computerisation threatens their jobs, which is a recognised limitation of adopting CAS.