In previous articles in this series, the key concepts and structures of developing a cost model were discussed. Important ideas to review are granularity, processes, level and special process cases.
- Granularity: Where in your portfolio of products/customers do you want to be able to calculate cost? The finest granularity is for an individual line item on an individual invoice. Higher granularity can be product groupings or even at the level of a single plant or office. There is no right answer. The decision rule is your measurement. Granularity should be the same as your required decision making.
- Processes: All products (and services) have a cost related to the business processes used in de-livering them. Process cost plus material gives total cost. Determining the processes you want to include is a balancing act between accurate detail and practical data measurement and collection.
- Level: This idea refers to how you desire to carve the total cost into different groups. The groups typically are considered incrementally variable, variable, semi-variable, semi-fixed and fixed. Se-lecting the groups properly will give you the best information about cost/volume relationships. The trade-off is complexity versus improved insights.
- Special process cases: We discussed several that can add some twists and turns to the calculation of cost. Review “Practical Costing Situations and Concepts” in June 2022 to check if these may impact your situation.
The Universal Cost Modeling Formula
At the risk of insulting every reader, the cost formula is simple:
Cost = Sum for each material and process required (quantity-each * cost-each)
The more difficult part is defining all the materials and processes and defining the numbers “quanti-ty-each” and “cost-each.” In some cases, quantity-each is easy if the engineering department has specified by design the quantity each required and the purchasing department can get vendor quotes clearly defining the cost-each. The amount of data, however, can be very large with material list run-ning hundreds or thousands of parts per product and the number of products in the thousands. The cost-each is usually harder for processes.
The Process Cost, Cost-each Calculation
Here is where the cost modeler earns their keep. Again, the formula is not hard.
Process Cost Each = Total cost for that process/total quantity produced
Your first challenge is to define a process in which you can collect from readily available data and data from which you can get periodic updates of the total cost of a process. Your accounting system may not collect cost by process, and you must prepare a pre-analysis to collect total cost by process. You may find that your process has a mixed bag of costs at various levels – from incrementally variable to fixed – and this cost must be broken into several pieces to analyze.
For example, you have collected the total cost for the “smushing department” for each of the last three years. The company ran that department for 1,000, 800 and 2,200 hours, respectively. In other words, the volumes were greatly different. You would need to break out variable and fixed costs to get good measures of total cost for your model.
The second challenge is the denominator: quantity. In some businesses, a single product quantity is a simple sum of the units produced. Once product complexity increases and the required quantity-each begins to vary, then a common basis for quantity must be developed. This common metric is usually hours, but it can be any number of quantifiable numbers – such as pounds of finished product, cubic feet of product, square feet of space utilized, pounds of a component product, man-hours, machine hours, cell operation hours, plant operation hours or other more clever and unique numbers.
The challenge for the cost modeler is finding common units for the denominator that best reflect the nature of the cost/volume relationship. Ideally, the relationship between the quantity in the denominator is fully linear with incremental costs, pretty linear with variable and semi-variable costs, and seems “ra-tional” as a way to split fixed costs. What does the term “rational” mean? If, for example, you were di-viding the cost of your maintenance expense (using square feet for the process department times quantity produced) as the denominator, that is more rational than quantity as the denominator. The process of spreading costs is called allocating costs; it is an art, not a science.
Choosing good denominators requires skill and experience. The CPA profession prefers the time-honored “direct labor hours” as a familiar and defensible GAAP compliant method. This made more sense in the days of high labor intensity and a high mix of variable to fixed costs. In today’s world, where automation has driven direct labor to relatively very low levels of total cost, this can be a very misleading denominator. Just think of a $2 million machine run by one operator versus a $100,000 machine run by two operators. Allocating overheads by labor hours could be very misleading.
Keeping Track of Incremental, Semi-variable and Fixed Costs is Important
Many business decisions require an understanding of the (up or down) impact on the business from a change in sales volume. We discussed these costs in “3 Core Concepts in Building a Cost Model” in April 2022. To improve the quality of your cost model, you should group and maintain all the costs in these buckets.
So, practically, what does that mean? A single cost element equals quantity-required times cost-each. As you develop the cost-each for incremental costs, it should include all the costs that are tied to the element. Take labor as a familiar cost element. You pay your workers $16/hour. You also pay their payroll taxes (10%) and some health-care costs ($8,000/year). Overtime is not allowed (for simplicity).
Their labor cost each hour is $16 + $1.6 + $4. While health care seems a “fixed cost” and many firms include it in SGA overhead unrelated to direct labor rates, the discerning analyst will understand that changes in employee counts are going to drive health-care costs. This simple example must be repeated for every process in your cost model. Maybe you will have one labor rate, or maybe you have some employees at $16 and some at $28.
A well-founded knowledge of the incremental, variable and fixed cost components of a product is critical to understanding margins and impacts the quality of all 10 of the reasons costing is important (see “10 Reasons Why Costing is Important” in February 2022).
Costing is hard. Unlike financial accounting, there are no GAAP rules that dictate right and wrong ways to cost. The goal of the cost modeler is to provide costs and margin estimates that are close enough to allow prudent tactical and strategic decision making. In many small businesses, owners “know” deep in their bones what makes them money and what does not. At some point in the maturation and growth of a business, especially should an owner desire to sell the business to a third party, costing and margins become critical.
I would argue that margin percentage is likely the single most important guide to the health and future success of a business, and understanding costs and how they impact margins is a critical skill for business success and survival. Call us if you need any help.
Author Peter Geise is Area President of FocusCFO.
He may be reached at 330-510-5760 or at p.geise@focuscfo.com.
For additional information, visit www.FocusCFO.com.
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