Easy Time Tracking To Enable Activity Based Costing (ABC)

November 25, 2010

Many large companies are concerned about measuring their business performance. It is not always obvious which departments, projects, products, and customers are more profitable and hence where the company’s focus should be. One approach that is helping the large organizations figure out their profitability is called Activity Based Costing. The model translates resource expenses into costs of basic activities constituting higher level projects and processes and from their derives product/service/customer costs. Such an analysis compared to the revenues generated by the corresponding product/service/customer helps to decide how resources should be used more effectively to maximize profitability.

You can find more detailed explanation of ABC on the Internet, here is just one interesting quote from http://www.asaresearch.com/articles/abc.htm:

Many experts believe that the best method for measuring a business may be “Activity Based Costing”. Some accounting software products such as SAP, Syspro IMPACT Encore, and Deltek offer strong ABC accounting.

The ABC model has a number of problems though that make its adoption quite problematic:

… the process of calculating activity expenses through interviews, observation and surveys has proven to be time-consuming and costly to collect the data, expensive to store, process and report, difficult to update in light of changing circumstances, and theoretically incorrect, by suppressing the role for unused capacity when calculating cost driver rates.

So an alternative approach for estimating an ABC model, called “time-driven activity-based costing,” addresses the above limitations. It is simpler, less costly, and faster to implement. Here is a great paper explaining TDABC and how exactly it is better than the original ABC model: Time-Driven Activity Based Costing. One of the key elements is how you measure an activity, and TDABC seems to be doing this by estimating time required by an activity:

The one new information element required for the time-driven ABC approach is an estimate of the time required to perform a transactional activity. As discussed earlier, an ABC system uses a transaction driver whenever an activity − such as setup machine, issue purchase order, or process customer request − takes about the same amount of time. The time-driven ABC procedure uses an estimate of the time required each time the activity is performed. This unit time estimate replaces the process of interviewing people to learn what percentage of their time is spent on all the activities in an activity dictionary. The time estimates can be obtained either by direct observation or by interviews. Precision is not critical; rough accuracy is sufficient.

I really liked the TDABC paper but I am sort of confused by these two statements:

  1. This unit time estimate replaces the process of interviewing people to learn what percentage of their time is spent on all the activities in an activity dictionary.
  2. The time estimates can be obtained either by direct observation or by interviews.

I understand that if you have the estimates you do not need the interviewing process. But, how exactly do you obtain these unit time estimates? The 2nd statement says, by interviews. So, do we get rid of the interviews or not? I am not sure what direct observation means exactly.

In any case the TDABC model makes alot of sense to me, and I like the idea of using time measurements instead of purely transactional measurements (10% – activity1, 20% – activity2, … = always 100%). I even think that you can do better than just the estimates. Organizations that use project management tools capable of time tracking could be collecting actual time measurements quite easily (depends on the tool of cause) all the time. Anyone tracking their tasks for PM reasons would automatically be logging time spent on the tasks. All that needs to be done additionally is proper categorization and directing that data into one of those TDABC systems (i.e. SAP, AcronSys, …)

So I am thinking the time measurements earlier generated by interviews could actually be a natural by-product of the PM task tracking process and will not be time consuming at all. A PM product that makes it very easy for people to track time could basically enable ABC/TDABC models for measuring business performance.

What do you think?


Here are two more links with more information on TDABC:




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