Product Specification Hints, Part 1

Executive Summary:

Product specifications are vital and powerful tools.  Written well, they provide focus and prevent waste.  If written poorly, they constrain creativity, and generate waste by causing design teams to chase their tails.  Make sure that your specifications define only needs, not solutions, and that they are clearly verifiable.

The Rest of the Story:

A product specification is a vital tool to a product development team.  It sets a vision for the product that it must design.  It defines what I call “what-done-looks-like.”  In short, the product specification gives focus to the development team and ensures it produces what is desired.

However, a poorly written or poorly understood product specification, or none at all, can create waste in the form of rework, defective or undesirable product designs, or just plain arguing over what the team is supposed to do.  Here I offer some lessons-learned regarding how to write useful product specifications.

A common mistake made in product specifications is to specify the solution.  I know, my choice of language begs an indignant rising of the eyebrows.  Let me explain.

When we specify a specific solution, we tie the creative hands of the design team.  We may even specify a poor solution without realizing it.  For example, if we are specifying an automobile, we can write a specification that states the vehicle must have a V8 engine.  Or, we can specify certain, torque, horsepower, and fuel efficiency performance values and let the design team decide what engine to use.

Years ago, when pickup trucks were becoming a seriously competitive market, Dodge released it’s full-ton truck with the Cummings Turbo Diesel engine, a big straight-6, while all the others issued large gasoline V8 engines.  The Dodge offering was a significant success because it provided excellent performance is all the right ways.

With every requirement, examine to see if it dictates performance criteria, or a solution.  Sometimes it can be difficult to tell the difference.  Here is my favorite test.  Simply ask the question, “why is that the requirement?”

If you answer, “because it will give the performance needed,” then what is specified is a solution.  If you answer, “because that is the performance that is needed,” then you have specified correctly.

When you write your specifications focus on the following three questions, and answer them in the simplest performance terms.

• What must it be?
• What must it do?
• Try to avoid answering the question, “what must it have?”

Many times, our development teams can create better solutions, especially for breakthrough not me-too products, if their designs are not constrained to provide the solutions specified, but are instead encouraged to develop solutions to meet the needs.

When you write your specifications, be sure to write them such that they are in verifiable terms and absolutely refrain from demanding performance to be the same as some other product.  In the end, a development team must prove they have met the specification and arguments over success or failure, or struggling to develop extraneous test methods and equipment to prove it has wastes time and resources.

Let’s look at an example.  Suppose you need your product to resist electro-static discharge (ESD) and an existing product does so.  If you say your new one must be as good as the old one because you want to ensure your customers see no degradation in quality, you have just created a problem and probably some waste.

Worst case, you now need to test several samples of both products in order to prove that the new one matches the old one.  That’s twice the testing.  If you are lucky and actually have a record of the old product’s test performance, you still have a problem.

Suppose that the old product meets 3010 volts of ESD resistance and your new product meets 2900.  It failed to meet the specification, but will your customers know the difference?  Of course not!  Suppose in order to meet the CE standards appropriate for your product it must only exceed 2000 volts of ESD resistance.  You could easily certify and sell that product instead of argue or redesign.

A product specification that defines the performance demands of your new product in clear terms, that can be measured and verified, and that allows the design team to create solutions is a powerful tool.  It inspires creativity and prevents waste by keeping the design team focused on specific, success-defining criteria.

A product specification that constrains creativity often leads to inferior products.  A product specification that is difficult to verify creates waste in the effort.  Follow the guidelines above and avoid making these mistakes.  If you are working to meet the needs of a specification, examine it carefully.  If you identify errors or problems, get them corrected quickly, before you go further.  Save yourself the waste.

Stay wise, friends.

P.S.  I have made available a guideline for writing product specifications.  Find it in the Download Helpful Solutions section of the bar to the right.