Let’s start with what productive struggle typically involves. The teacher chooses a new understanding and instead of leading with highly supportive models of instruction (e.g., worked models of correct responding, immediate corrective feedback, and gradual release of support), the teacher presents the task to be learned with minimal guidance and students are encouraged to work on the task (this is the struggle) often in collaboration with classmates to “figure out” a solution (this is the productive part) and the theory imagines that the skill development that results from this experience will be more robust.   

No evidence suggests giving students minimal guidance when learning new skills leads to better learning.⁴ In fact, fact, high-quality experimental research favors the use of systematic and explicit instruction for all learners when learning new skills. Importantly, the principles of systematic and explicit instruction are at odds with the theory of action of productive struggle.⁵,⁶ The data favoring systematic & explicit instruction are so robust that explicit instruction is a recommended practice for general math instruction, whereas productive struggle is not.⁷

In direct contrast with productive struggle, research evidence shows that students learning
new skills require clear demonstrations and guided practice with immediate feedback and the types of instructional tasks described here https://ies.ed.gov/ncee/wwc/Docs/PracticeGuide/WWC-PraxGuide-Elementary-Math-Summary-508c.pdf.⁸

New concepts are not learned by struggling. Children best learn when they are supported to respond with ease and accuracy as they are learning new skills and understanding, then advance to productive skill practice to make correct responding easier (i.e., build fluency), and then are given opportunities to generalize their learned skills.²