Capability

Capability simply means that a person or machine has the ability to perform a required task. It is a binary measure. That simply means that it is physically possible in the current state to do something, or it is not.

Capability should not be confused with yield or effectiveness (how good the resources is at doing the process), or with capacity (how often the resource can complete a task.)

For a machine, capability means that the task falls within the function of the machine. Obviously, a drill press cannot bend metal. But that drill press may also be limited by the size of the hole it can make, the weight of the product is working on, the ability to access recessed areas, and so on.

For a person, capability can fall into the physical spectrum or can be related to training. For the physical side, physical capability determines whether a person can reach into a tight area, hold a miniature component, lift a heavy weight, and the like. Basically, it means the person’s body can perform the required task.

On the training side, it is a bit less clear. While a person can be trained to be capable of doing something, it does not mean that they are effective at it. Think of trying to hit a fastball. You could take a person with no skills or training in swinging a baseball bat to a batting cage. You could give them a rudimentary lesson and send them in to hit a pitch. Does their training make them capable of hitting the ball? Yes.

Is it likely that they will be successful in any sort of consistent fashion? No. Capability is only the first hurdle to overcome. They must also be trained to be consistently effective.

To reinforce the point made earlier, capability simply means that it is possible to do a task. It does not mean that the task will be consistently performed up to standard.

The above is a generic explanation of capability. There is a measure known as the process capability index that addresses whether an operation can, statistically speaking, consistently meet its targets. Essentially, it indicates if the historical spread of the process is capable of fitting within the tolerance spread of the customer’s requirements.

Capability, Capacity, and Yield

When determining whether or not an operation can deliver the results you want, it is not enough to simply look at capability. That is simply the first step to determining whether producing the item in question is even an option. You also have to look at the capacity of the resources doing the process. That will tell you how often a cycle of production can be completed. But even that is not enough. Yield is a measure of how effective the process is in producing a good part. You might have sufficient capacity, but if half of the production is done incorrectly, you would miss your targets.