Advantages and Disadvantages of Activity Based Costing in Modern Accounting

Every company that makes more than one product runs into the same accounting headache eventually: how do you fairly split overhead costs like factory rent, machine maintenance, and quality checks across different products? Traditional costing methods often spread these costs using a single, broad measure like direct labour hours, which can badly distort the real cost of a product. Activity Based Costing (ABC) was developed to fix exactly this problem, and it remains one of the most widely discussed tools in modern management accounting. This post breaks down what ABC actually is, how it works step by step, and why it comes with both real advantages and real limitations.

What is activity based costing? 🔗

Activity Based Costing is a costing method that assigns overhead and indirect costs to products and services based on the actual activities that drive those costs, rather than an arbitrary allocation base. The core idea is simple: activities consume resources, and products consume activities. So instead of asking “how many labour hours did this product use,” ABC asks “how many times was this product inspected, set up, or ordered,” and assigns cost accordingly.

The concept traces its roots to 1971, when the term was first used at the University of California, Berkeley. It was later formalised by Robert Kaplan and William Bruns at Harvard Business School in the late 1980s, which is why the method is often credited to them. ABC gained traction first in manufacturing, where overhead costs like machine setup, material handling, and quality inspection can be substantial, but it has since spread into service industries, banking, and healthcare as well.

Why traditional costing falls short 🔗

Traditional absorption costing was designed at a time when companies made a narrow range of products and overheads were a small part of total cost. Back then, spreading overheads using direct labour hours was a reasonably fair approximation. But as factories became more automated and product ranges diversified, overheads started forming a much larger share of total cost, while direct labour shrank. Using an outdated allocation base in this new environment often means high-volume, simple products end up subsidising the true costs of low-volume, complex products, leading to mispriced goods and poor strategic decisions.

David Cooper and Robert Kaplan wrote extensively on this problem in the early 1990s, arguing that companies needed a system that could reflect the true cost of a product by tracing overheads to the specific activities that caused them, rather than allocating them on a single, generic basis.

The building blocks of ABC 🔗

To understand how ABC actually works, it helps to know four key terms that appear throughout the method.

The Chartered Institute of Management Accountants (CIMA) defines ABC as an approach to costing and monitoring activities that involves tracing resource consumption to activities, and then to the final cost objects using cost drivers. This two-stage assignment, resources to activities, and activities to products, is what sets ABC apart from traditional methods.

Steps involved in implementing ABC 🔗

Setting up an ABC system generally follows four broad stages. Each one requires close coordination between the accounting team and operational staff who actually understand how work gets done on the shop floor.

1. Identifying activities 🔗

The first step is mapping out every significant activity that consumes resources within the organisation. This could include machine setup, purchase ordering, quality inspection, packaging, and dispatch. The goal is to be granular enough to capture meaningful cost differences without creating an unmanageably long list.

2. Classifying activities into cost pools 🔗

Once activities are identified, related costs are grouped into cost pools. All expenses connected to a similar activity, such as wages of quality inspectors, testing equipment depreciation, and lab supplies for a “quality control” pool, are bundled together.

3. Assigning cost drivers 🔗

Each cost pool needs a cost driver that has a strong cause-and-effect relationship with the activity. Machine hours might drive machining costs, while the number of purchase orders might drive procurement costs. Choosing the wrong driver is one of the most common reasons ABC implementations produce misleading results.

4. Calculating cost per activity and assigning to products 🔗

Finally, the cost per unit of the driver is calculated by dividing the total cost pool by the total quantity of the driver. This rate is then applied to each product based on how much of that driver it actually consumes, giving a far more precise picture of what each product truly costs to make.

Advantages of activity based costing 🔗

ABC’s popularity in accounting curricula and corporate finance departments comes down to a handful of genuine benefits.

More accurate product costing 🔗

By tracing overheads to the activities that actually cause them, ABC gives a much more realistic picture of what each product or service costs. This is especially valuable when a company makes a diverse product mix with varying levels of complexity.

Better pricing and profitability decisions 🔗

With accurate cost data, managers can set prices that reflect true resource consumption instead of guesswork. Some studies suggest that the pricing precision offered by ABC can help companies uncover meaningful cost savings each year simply by identifying products that were previously underpriced or overpriced.

Identifying inefficiencies and non-value-added activities 🔗

ABC forces an organisation to examine every activity closely. This often exposes non-value-added activities, tasks that add cost without adding market value, such as excess inventory storage or redundant inspection steps. Once identified, these can be streamlined or eliminated altogether.

Supports strategic decision-making 🔗

Because ABC data shows true product-level profitability, it becomes a useful input for decisions on make-or-buy, product discontinuation, and customer profitability analysis, decisions that are much harder to make confidently with a blunt, single-driver costing system.

Disadvantages of activity based costing 🔗

Despite its strengths, ABC is far from a perfect system, and its drawbacks explain why many organisations hesitate to adopt it fully.

Time-consuming and complex to implement 🔗

Identifying every activity, cost pool, and driver across an entire organisation requires considerable effort and expertise, and can take months to set up properly. Smaller finance teams often struggle to dedicate the resources needed.

High implementation and maintenance costs 🔗

Collecting and continuously updating data for numerous activities and cost drivers is expensive. For smaller organisations, the ongoing cost of maintaining an ABC system may outweigh the benefits it delivers, which is why ABC tends to be more common in larger, complex manufacturing setups.

Some costs remain arbitrary 🔗

Not every cost has a clean, traceable driver. Facility-level costs such as security, general lighting, and top management salaries are difficult to link to any single product or activity, and often still need to be allocated on a somewhat arbitrary basis, undermining the precision ABC promises.

Not ideal for every organisation 🔗

ABC works best where overheads are large and diverse, and product lines vary significantly in complexity. Organisations with a narrow product range or relatively low overhead may find that the effort of implementing ABC isn’t justified by the improvement in decision-making it provides.

Where ABC fits in modern accounting 🔗

ABC isn’t meant to replace every other costing system; it’s a tool best suited to specific situations. Manufacturing firms with diverse product ranges, high automation, and significant indirect costs tend to benefit the most. Service industries like banking and healthcare have also adopted variants of ABC to better understand the true cost of processing a loan application or treating a patient. At the same time, simplified variants such as time-driven activity based costing, developed later by Kaplan himself, have emerged to address some of the complexity and cost concerns of traditional ABC, using time estimates rather than exhaustive activity surveys to assign costs.

What do you think? Would a mid-sized manufacturing firm in India with a narrow product range benefit more from adopting ABC, or would the implementation cost outweigh the gains? And in service-heavy sectors like banking, where activities are less physical than in a factory, how easy do you think it would be to define clean cost drivers?

References

1. https://www.aicpa-cima.com/resources/article/activity-based-costing-abc
2. https://mbaknol.com/financial-management/activity-based-costing/
3. https://www.freshbooks.com/en-au/hub/accounting/pros-and-cons-of-activity-based-costing
4. https://managerialaccounting.org/activity-based-costing.html