Nintendo redefines how to look at attach rates on Switch

Very unique way to forecast sales of games based on hardware sales.

Nintendo President Furukawa explained the reasoning behind ther new Sales Per Hardware Unit metric at the financial presentation:

I’d now like to address the Nintendo Switch business from a slightly different angle. One conventional metric used in the dedicated platform business is the tie ratio, or the attach rate of software per unit of hardware. This is calculated by dividing the number of software units sold by the number of hardware units sold. However, with the rise in digital sales, we are witnessing the rapid sales growth of indie titles at a wide range of price points, and add-on content sales that cannot be counted with the number of software units sold. As a result, software attach rate calculated using conventional methods no longer adequately reflects the actual state of our business.

Instead, we would like to look at "sales per hardware unit," which is the overall sales for the platform divided by sales of the hardware itself. Note that this is calculated based on sales recognized by the company, and it differs from individual consumer spending.