Hi, Jim.
I’ll take a closer look at the deck course, article, and gallery. Thanks for bringing this up to our attention. I don’t follow the forum much, so you can email education@internachi.org if you or anyone ever finds an issue with any training content. Thanks for helping us keep our curriculum accurate and up-to-date.
We have a new article with information about stringers that may be interesting to you. Visit https://www.nachi.org/inspecting-stair-stringers.htm