I am so glad this thread was brought up! I have read through it and it has been highly informative. It would be awesome if this thread were shared in the facebook group Carseats For The Littles, because I was recently banned from there for stating the rule "every step up is a step down in safety" and "consider harnessing until child outgrows the seat limits". What I've learned here is there is not enough data to say EHing is exponentially safer than boostering (assuming both are used correctly), but it is likely that a booster seat is more likely to be misused or used before the child is mature enough. When I do become a certified tech (my area is in desperate need - all of the local so called "techs" that work with the health department spread misinformation and do not advocate for ERFing) I likely will still repeat "every step up is a step down in safety", but continue to place most importance on rear facing. It seems in my area seats that have the potential to forward face to 65lbs are extremely popular, and if I can encourage people to harness to the limits of such seats, I'd be quite pleased.