At first sight, this paper seems a bit of an indictment of formative assessment – no effects in an RCT
Then you look at its size (N=12 teachers), the varied implementation, and the way almost no student or school characteristics were controlled for.
And you realise that fundamentally it highlights how we struggle to support teacher change.
Yin, Y., Shavelson, R., Ayala, C., Ruiz-Primo, M., Brandon, P., Furtak, E., Tomita, M. and Young, D. (2008). On the Impact of Formative Assessment on Student Motivation, Achievement, and Conceptual Change. Applied Measurement in Education, 21(4), pp.335-359.