An empirical study of organizational learning in semiconductor fabrication facilities finds that 1) the external economic environment strongly influences the value of different kinds of organizational learning; 2) the value of organizational learning varies over time; 3) the relative value of different kinds of learning varies over time; 4) the value of learning can be positive or negative; 5) the synergy between different kinds of learning can be positive or negative; and 6) useful theories of organizational learning must be value-driven and time sensitive. The approach described in this paper helps factory managers enhance profitability by choosing appropriate learning strategies for the particular product mix that a fabrication facility runs.