A- As a consumer of quality wood flooring, you naturally want to know how the product you are thinking about purchasing will withstand wearing and dents. The Janka hardness rating is your standard measurement for this purpose. The Janka test is conducted by measuring the force needed to lodge a .444-inch steel ball in the wood species to a depth of half the ball’s diameter. The higher the rating, the harder is the species of wood. Of course, the Janka hardness rating is also useful when assessing how easy or difficult it is to hammer a nail into the hardwood or cut it with a saw.