This hat is a ladies small. The hat is knitted flat. To make a larger hat while still maintaining the pattern, you would have to cast on 10 more stitches.

Stitch patterns used in this pattern are mentioned in the Pattern Post here:
http://smariek.blogspot.com/2006/10/claudia-hat.html
and also in the Pattern Bibliography post here:
http://smariek.blogspot.com/2007/11/pattern-bibliography.html
.