Wisdom from Bob Lewis, in 2 parts.
1) Metrics prevent good things from happening:
"Certifications are metrics, which is to say they’re supposed to be a way of telling whether or not someone has achieved the results they’re supposed to achieve. What, you thought a metric had to be a number?
And every time the metric becomes the point, whether it’s a college student wanting a diploma instead of an education; a supplier wanting ISO-9000 certification instead of wanting top-notch internal processes; or a retailer seeking PCI compliance instead of well-protected customer data … every time the metric becomes the point it prevents something good from happening.
And once you have a metric, it rare that it doesn't become the point."
2) Testing measures motivation, not mastery:
"Boiled down to basics, certification means passing a test. So far, so good — tests are designed to gauge knowledge and competence. But (and you knew “but” was hanging over that sentence like the Sword of Damocles) …
Those taking the test have a personal stake in passing that exceeds their personal stake in acquiring knowledge and becoming competent. If they’re job-seekers their careers depend on it; if they’re retailers, their ability to receive payments with something other than cash depends on it, if they’re cramming for the SAT their college entrance and future careers depend on it.
Those who seek certifications are incented to pass the test. Achieving actual competence becomes the byproduct, not the point."