Question: When assembling stair treads and risers, is it better to have the tread tucked under the riser or have the riser tucked in between the tread and the stringer riser backing? I am inclined to think the former because that way the tread gets more framing support but the way my current stairs are assembled is the latter, hence my uncertainty. 

See picture.![enter image description here](https://i.stack.imgur.com/4Me0r.jpg)

Answer: 
We installed it so the tread goes under the riser. We installed hardwood stairs in our home and we cut the bottom of the riser at a slight angle to ensure that the front edge of the riser was always fully touching the tread so you couldn't see a gap between the riser and tread. 

I see a lot of places online that say to install the riser first and then install the tread (riser touching the stringers and tread in front of the riser), but I can't honestly think of a reason why it matters. Maybe someone else has a polarizing opinion, but I think either is fine.
It comes down to flow. From top to bottom on any assembly you should build it so water flows downward and not inside the assembly. If the riser is installed first and the tread pushed up to it, any liquid, dirt or dust falls in between the tread and the riser. This could cause grief, and in the case of dirt be rather unsightly. With water the water flows under the tread. With all building assemblies there is the easy way, riser then tread, and the right way, tread then riser. The latter being more mathematical to assemble due to the mop and skirt boards. Always think of how water flows when building anything even if you believe water will never enter the picture.