Attributes with Costs

Consider medical diagnosis, $BloodTest$ has cost $150 robotics, $Width\_from\_1ft$ has cost 23 sec.

How to learn a consistent tree with low expected cost?

One approach: replace gain by

Tan and Schlimmer (1990)

$$\frac{Gain^{2}(S,A)}{Cost(A)}.$$

Nunez (1988)

$$\frac{2^{Gain(S,A)} - 1}{(Cost(A) + 1)^{w}}$$

where $w \in [0,1]$ determines importance of cost