Difference between Capability Level and Maturity Level

The Concept of capability level and maturity level

The ISO 15504 defines a capability level and CMMI defines both capability
level and maturity level. Now what exactly is the difference between capability
level and maturity level. I shall try to explain the difference using an


Maturity levels in real life

Consider a person named M. When he was a child just one year old, just like
any other one year old, he could barely walk and speak. For our analogy purpose
we consider this stage as level one.

Now we look at person M again when he is a five year old child. At this stage he
can walk and run, and has basic reading and writing skills. This stage is level

When M is a 15 year old student, his reading and writing skills have developed
significantly, has knowledge in a variety of subjects and is developing his
analytical and problem solving skills. This is level three stage.

At 25 years of age, he has completed his professional education and has started
working in an organization. He is now applying his writing, speaking and
analytical skills for his professional purpose and now he also has the skills to
drive a vehicle. This stage is identified as level four for our analogy.

Years pass by and Mr.M now runs his own business. He has successfully applied
his planning and decision making skills to make his business venture a success.
We identify this stage as level five for our analogy.

Now let us look at these different stages closer. We see that as M passes
through these stages, he acquires more skills and his proficiency in most of the
acquired skills keep improving. He never really loses any of the acquired
skills. If we now look at these skills as different Process Areas in CMMI, we
can understand how an organization matures through different levels.

That is how maturity levels are defined. It defines whether the organization
has the ability or skills in the specified process areas. Sometimes
demonstrating a basic proficiency in one particular process area may be
sufficient for the organization to pass through a maturity level.


Capability levels in real life

Capability levels in ISO 15504 and CMMI are very similar and are defined from
zero to five. At level zero, the process is not performed and at level five the
process is continuously improved.

To use an analogy similar to the one used for explaining maturity levels, we
now consider the following persons:

Mr.A is a world renowned athlete and has won several Olympic medals in

Mr.J is a noted writer who has won several awards for his literary works.

Ms.S is a famous singer who has won several awards for her performances

Mr.W is the president of a fortune 500 company and is known for his highly
successful management styles

Now if we look at these people closer, we see that they all have writing,
singing, running, analytical and judgment skills, but in varying degrees. These
differences in proficiency can be defined as capability levels.

As an athlete, Mr.A has highly developed running skills better than anyone else.
So his capability in running can be considered to be at the highest level. His
abilities in other areas such as writing, speaking, etc., are average, which
means they could be considered to be at levels two or three.

Mr.J has very good imagination and language skills that he applies in his
literary works. But he can never compete with others and win in any activity
that requires physical exertion.

In the same way, Ms.S and Mr.W has excellent skills in specific areas, and their
skills in other areas could be considered as average.

Capability levels like proficiency in skills are defined for each process
area. Just as it is impossible for a person to be a proficient athlete, writer,
musician and a successful business man all at the same time, it is highly
impractical for an organization to achieve capability level five in all process

So what is the ideal capability level you need to achieve for each process

Just as a person need not have the highest proficiency in all skills to be
successful, an organization can very well be successful with a capability level
two or three for most process areas. Depending on the domain of work or type of
projects being executed, the organization can look at specific process areas to
be at capability level three or four. Other than that there is no business case
for trying to achieve anything over capability level three for any process area.

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