Does journal writing impact students' ability to DO a math problem? Is less more? Do we really need to assign 15-30 problems after each class period?

I am looking for ways to incorporate more writing and critical thinking in my courses without losing the "how to" perform mathematical operations and procedures.

I have been teaching calculus III since Fall 2008. In Spring 2013, students used a workbook I created with practice problems after each section. These homework sets would be collected the next class period, and a grading frenzy would occur (class size is typically 30-32 students in calculus III). In Spring 2018, I decided to not collect these homework packets and have students only journal. See previous CATS to explain journaling in my course.

From Spring 2013 - Spring 2016, I have taught 7 different sections of calculus III which includes 187 different students. Of 187 students, 18.1% of them failed the 1st exam. Note: Calculus III has a different level of student - typically these students have also taken chemistry, physics and engineering. These students understand how to study. Spring 2018 - I had 100% of my 31 students pass the 1st exam. I used the same workbook and PowerPoints, too.

As a math instructor at EMCC for 16 years, I have always believed students must practice. They have to do 20+ problems outside of class in order to be able to DO problems on exams/quizzes. From working with physics and chemsitry faculty over the years and seeing what they do with journals, I have been hesitant to try this. "Math is different. Math is skill based, and you don't get good at this unless you practice over and over again," I would think to myself. It took me 16 years to get to this "aha" moment, and I am so excited about this. The more I learn about how we all learn, the more I want to try new things outside of the "norm" of mathematics instruction.