[2]: 73  Duffy is distinctive largely because of its pottery: the site's inhabitants typically produced ceramics of various thicknesses and comparatively few decorative elements, tempered with grog.

[2]: 82  What decorations exist are typically limited to one or two rows of simple lines or bars that have been incised or stamped on the side of the piece of pottery.

Like Duffy,[2]: 82  the people of Yankeetown produced grog-tempered pottery with few details other than incisions,[3]: 2  although differences between Duffy and Yankeetown pottery are substantial enough to rule out a close connection between the two peoples.

[2]: 82  Nevertheless, the two sites share certain cultural influences: both feature Late Woodland elements,[4]: 156  and as Yankeetown appears to show the beginnings of an indigenous form of the Mississippian culture,[3]: 3  Duffy bears some evidence of Mississippian influence.

The latter site appears to have been under Duffy control as the region was transitioning from terminal Late Woodland to Mississippian.