By validation I mean comparing values generated by a model with actual values to determine how well the model reproduces what it was intended to re produce. Clearly evaluation involves more than this. Evaluation involves judging the appropriateness of the estimation procedures and judging the use made of prior econotnic knowledge in constructing the model. A model can be validated by determining its performance during the sample period, or by deter mining its predictive performance in the post-sample period.
Ladd, George W., "Evaluating Econometric Models And Forecasts" (1976). Economic Staff Paper Series. 150.