I am frequently amazed by how often cost engineers will gloss over assembly operations and treat them as a small line item, a rough “catch-all” assumption, or a brief cost model element labeled as “someone just puts it together.” But that simple act within a cost model can hide a lot of activity: reaching for parts, orienting them correctly, finding the right angle, starting a fastener, checking fit, handling a tool, moving material, or dealing with a fixture that almost works but not quite. These little motions are easy to underestimate during quoting and design reviews. On the factory floor, though, they show up as real time, real labor, and real cost.  That is exactly where Methods-Time Measurement, or MTM, becomes valuable.

What is Methods-Time Measurement?

MTM is a predetermined motion time system used to analyze manual work. In simpler terms, it breaks a job into basic human motions, such as reaching, grasping, moving, positioning, releasing, turning, walking, bending, and using visual control. Each motion is assigned a standard time based on the nature of the motion and the conditions under which it is performed.

For a cost engineer, the important point is this: MTM does not begin with the question, “How long did someone take?” It begins with the question, “What method is required, and what time should that method take?”

That difference matters greatly. A stopwatch study can tell us what happened during an observed operation. MTM can help us estimate what should happen before production begins. That makes it especially useful in cost engineering, where decisions often need to be made while the design is still changing, suppliers are still quoting, tooling has not been built, and the final workstations may not even exist yet.

The basic idea behind MTM is that labor time is not random. Manual time is driven by the method. If an operator must reach farther, turn a part over, visually align a feature, pick up a tool, apply pressure, or walk to a bin, those actions consume time. If the product is redesigned so the part self-locates, the fastener is easier to start, or the component is presented in the correct orientation, the time goes down. MTM gives teams a structured, proven way to see those differences.

That is why MTM fits so naturally with cost engineering. It connects product design, process design, labor content, and cost. Instead of assigning labor based on a broad rule of thumb, such as “two minutes for assembly,” MTM helps show where those two minutes come from. This kind of visibility is valuable when building should-cost models, reviewing supplier quotes, supporting design-to-cost work, or evaluating automation.

MTM also helps cost engineers communicate with other functions more concretely. A design engineer may see a small clip, screw, bracket, or connector as a minor feature. Purchasing may see only the piece price. Finance may see labor as a standard cost input. Manufacturing may see the real struggle of installing the part repeatedly over the life of the program. MTM helps translate that shop-floor reality into time and cost terms that everyone can understand.

The History of MTM

The history of MTM goes back to the broader field of motion study. In 1911, early pioneers such as Frank and Lillian Gilbreth studied how workers moved and searched for ways to remove wasted effort. Later, Harold B. Maynard, John L. Schwab, and Gustave J. Stegemerten developed the MTM system by filming and analyzing manual operations in detail, frame by frame. Their work led to the 1948 publication of a book entitled “Methods-Time Measurement”, which became the foundation of the MTM approach we use today.

The original system is known as MTM-1. It is the most detailed level of MTM and is built around very specific basic motions. These include actions such as reach, grasp, move, position, release, turn, apply pressure, eye focus, body movement, foot movement, and walking. MTM-1 uses Time Measurement Units, or TMU, as its time basis, where one TMU equals 0.036 seconds, so one second is about 28 TMU.

Because MTM-1 is highly detailed, it is best suited for short-cycle, repetitive work where small motion differences matter. High-volume assembly is a good example. In that kind of environment, a small design or method improvement may save only a fraction of a second per cycle, but that fraction can become meaningful when multiplied across hundreds of thousands or millions of units.

From a cost engineering perspective, MTM-1 can be especially helpful when analyzing detailed manual assembly content. It can show the labor impact of fastener selection, access direction, component packaging, fixture design, reach distance, hand clearance, part symmetry, and inspection requirements. Those are not abstract manufacturability issues. They are cost drivers.

Evolution of MTM

As time went on, other MTM systems were developed to make analysis faster when the full detail of MTM-1 is not needed. MTM-2 is a higher-level system derived from MTM-1. It combines basic motions into larger motion groups. This makes it quicker to apply while still being connected to the same basic idea: time follows method. MTM-2 is often useful when the work is repetitive enough to benefit from structured analysis, but not so detailed that every small motion must be coded individually.

MTM-UAS, or Universal Analyzing System, is another commonly used level. It is often applied in batch production or mixed-model environments where the analyst needs a practical balance between detail and speed. MTM-UAS groups work into broader activity categories, such as getting and placing objects, handling tools, operating equipment, performing body motions, and carrying out visual controls. For cost engineers working on early estimates or supplier cost reviews, this level can be very practical because it supports credible labor analysis without becoming too slow or overly detailed.

MTM-SD, or Standard Data, is used for longer-cycle work and planning applications. It can help with labor planning, capacity studies, line balancing, and estimating. There are also specialized MTM systems for different kinds of work. MTM-LOG supports logistics and material handling. MTM-MEK is used for small-lot, one-off, or long-cycle work such as equipment build, repair, maintenance, setup, and changeover. MTM-VI focuses on visual inspection, while MTM-OS applies MTM thinking to office and administrative processes.

These different levels matter because not every cost problem needs the same tool. A cost engineer estimating a high-volume connector assembly may need a detailed motion-level analysis. A team reviewing a supplier quote for a lower-volume fabrication may only need a higher-level MTM structure to test whether the quoted labor makes sense. The key is choosing the right level of detail for the decision being made.

How Does MTM Work ?

The first step is to define the method. This is the most important part, and it is also where MTM becomes more than a timing exercise. The analyst must understand how the work will actually be done. Where are the parts located? Are they bulk-packed, tray-packed, or presented in orientation? How far does the operator reach? Is the part easy to grasp? Does it need to be turned? Does it self-locate? Is a fixture used? Is a tool required? Can the operator see the installation point? Is there a required inspection step?

Once the method is defined, the work is broken into motion elements. For example, installing a small screw might include reaching for the screw, grasping it, moving it to the joint, positioning it, reaching for the driver, engaging the bit, applying pressure, driving the screw, releasing the tool, and visually confirming the result. Each of those actions has a time value. The values are added together to create the standard time for that defined method.

Benefits of Using MTM

This structure gives cost engineers something very useful: a labor estimate that can be explained. If the estimated assembly time is 45 seconds, MTM can show why. It can also show what would have to change to reduce it to 35 seconds. Maybe the part needs better presentation. Maybe the fastener should be replaced with a snap-fit feature. Maybe the fixture needs a locator pin. Maybe the operator is spending too much time orienting a nearly symmetrical part. MTM turns those ideas into measurable cost opportunities.

MTM is also useful during supplier quotation analysis. Suppliers may quote very different labor times for the same part or assembly. Sometimes the difference comes from labor rates, but often it comes from method assumptions. One supplier may assume manual sorting from a bin. Another may assume automation or pre-oriented parts. One may include inspection time. Another may not. MTM gives purchasing and cost engineering a common language for challenging, validating, or normalizing those assumptions.

The same logic applies to manufacturability reviews. Design for Manufacturing and Assembly, or DFMA, often focuses on reducing part count, simplifying fastening, improving access, and making assembly more foolproof. MTM supports that work because it shows the time impact of design choices. A part that can only be installed in one awkward orientation will carry more labor cost. A feature that requires visual alignment will add time. A connector hidden behind another component will slow the operation. These issues are easier to address before release than after launch.

For finance professionals, MTM may seem more operational than financial at first glance. In reality, it supports several financial decisions. Labor standards affect product cost, margin forecasts, manufacturing budgets, staffing plans, capacity investment, automation payback, and make-versus-buy analysis. When labor time is estimated too loosely, the business case can look better than reality. When labor time is understood clearly, financial forecasts become more dependable.

MTM does not replace engineering judgment, supplier knowledge, or actual production data. It also depends on trained analysts and a clearly defined method. Used poorly, it can create false precision. Used well, it gives teams a disciplined way to understand manual work before cost mistakes become locked into the product and process.

In Summary . . .

For cost engineers, MTM is worth knowing because it helps answer some of the most practical questions in our field: What should this operation cost? What labor content is really required? Which design choices are driving assembly time? Is the supplier’s quoted labor reasonable? Would automation pay back? Can manufacturability be improved before production begins?

Manual assembly operations may look like a small part of the cost model, but they often carry hidden complexity. MTM gives us a way to make that complexity visible, measurable, and actionable. In a competitive environment where small differences in labor time can influence sourcing, pricing, margin, and launch performance, that visibility is not just an industrial engineering detail. It is a cost engineering advantage.

Jeff Miller is President and Co-Founder of SPCEA and has 40 years of engineering, manufacturing, and commercial experience within the electronics and semiconductor industries. He has served in leadership and direct-contributor roles at General Motors, John Deere, Standard Motor Products, Ford Motor Company, Whirlpool Corporation, and Panasonic Automotive Systems. Jeff has been active within the cost engineering profession since 2002.  Copyright © 2026 – Society of Product Cost Engineering & Analytics. All rights reserved.