[raganwald]

If someone has a CS degree I should be able to talk about garbage collection, threads, the pumping lemma, Amdahl's Law, control flow, NP-Completeness, etc...

Has this been your uniform experience? Consider the following thought experiment: We advertise for a position as a programmer. We state that we require a CS degree. Within the set of applicants, what correlation will we observe between the ability to speak knowledgeably about all or even most of the subjects you list and a degree?

I suspect the correlation will be higher with a degree than without it, but too low to be useful for screening applicants in and of itself. This is not a fault of your reasoning, but rather a fault of the current system, where each institution decides for itself what is and isn't part of the curriculum and many (but not all!) undergraduate programs have been moving inexorably towards vocational training rather than teaching Computer Science.

Scarcity really should have nothing to do with it. Either you've acquired the knowledge, in which case the degree signals that or you haven't.

If the knowledge you describe is not scarce, than signalling that you have this abundantly distributed knowledge is not particularly meaningful. Let's say that the degree works exactly as you suggest: Everyone with a degree can and does have strong knowledge of the exact subjects you mention. But let us further say that this is not scarce: When we advertise for a position, 80% or more of the applicants have a degree and the knowledge that goes with it.

How then does this degree help us go from 100 applicants to five interviews? Sure we might choose to throw twenty resumés away right off the bat, now our problem is going from 80 applicants to five interviews. In this scenario, a degree is not meaningful to us because it doesn't help us make a decision.

Thus, we are forced to consider other factors, such as job experience, contributions to open source, writing on line, and so forth. Those factors become more meaningful because they are scarcer.

Sure, there will always be some meaning to a degree, but its utility for making a decision is a function of its scarcity in the sample set.

[kenjackson]

If the knowledge you describe is not scarce, than signalling that you have this abundantly distributed knowledge is not particularly meaningful. Let's say that the degree works exactly as you suggest: Everyone with a degree can and does have strong knowledge of the exact subjects you mention. But let us further say that this is not scarce: When we advertise for a position, 80% or more of the applicants have a degree and the knowledge that goes with it.

How then does this degree help us go from 100 applicants to five interviews? Sure we might choose to throw twenty resumés away right off the bat, now our problem is going from 80 applicants to five interviews. In this scenario, a degree is not meaningful to us because it doesn't help us make a decision.

I'm not sure what scarcity has to do with it. Either the skills are useful for the job or they're not. For example, being 7 feet tall is rare. But it's probably not something you care about.

What you really should do is enumerate the set of attributes that are valuable. And there are generally two types, those that are binary, and those for which more of the attribute is desirable (invert the attribute for negative attributes).

Now if the degree captures a lot of the attributes, especially the binary ones, and further if you think those w/o the degree don't have it then it is useful to list. Unless you really believe that the sample set contains 95% people with degrees.

The nice thing this allows you to do then is to focus on other aspects that you value. And for the ones that aren't binary is where you spend most of your time drilling. It's not about scarcity, its about optimizing.

[raganwald]

Unless you really believe that the sample set contains 95% people with degrees.

That's the whole point. The value of the degree is the inverse of its scarcity. If you have 50% of people with degrees, it's more useful than if you have 80%, which is more useful than if you have 95%.

Perhaps you misunderstand what I am saying?

I'm not saying a degree isn't useful or meaningful.It is not a boolean, meaningful or not meaningful. Just that it is more useful and more meaningful if a degree is scarce than if it is plentiful.

We don't need to agree or disagree on whether the lack of a degree signals the lack of knowledge or whether we have confidence that those with degrees really do have all of the skills we seek.

Just that the scarcer it is, the more meaning we apply to it.

[kenjackson]

That's the whole point. The value of the degree is the inverse of its scarcity. If you have 50% of people with degrees, it's more useful than if you have 80%, which is more useful than if you have 95%.

The value of the degree, to you, trying to whittle down applicants, is inversely related to scarcity. But not to the degree holders. In fact, as the scarcity decreases, the cost of not having the degree may increase.

There's effectively two states: (1) Have the degree (2) Don't have the degree.

In a world where the degree is scarce having the degree may provide more value over the average person (although if it is too scarce, the value may actually diminish, as it may also hinder its credibility or recognition). But at the same time, not having the degree doesn't reduce your value as much versus the average person (since its rare, no one notices its absence).

When the degree is common, the opposite is the case.

What I'm trying to say is that scarcity matters to you in a very isolated activity (whittling down applicants). Outside of that, the role of scarcity plays both sides of the fence.

[raganwald]

That's really interesting, thanks!