The fund provides solid exposure to the US small-cap growth market by tracking a CRSP index. CRSP classifies growth securities using fundamental factors such as 3-year historical growth in EPS, growth in sales per share, current investment-to-assets ratio, and return on assets. Securities are scored and ranked based on the composite of these growth factors, which is also the basis of their weighting. The resulting portfolio gives representative coverage of the mid-cap growth space. Vanguard attempts to fully replicate the index, holding each stock in approximately the same proportion as its weighting in the index. The index is fully reviewed on a quarterly basis.