One of the most important aspects of STEM is the development of 21st century skills, including how we access information and use it to solve problems and communicate effectively (Vasquez, Sneider, & Comer 2013). Accessing information and problem solving are addressed in all four of the best practices, but collaboration, the process of working cooperatively and solving problems based on communication with others, is important enough to be a best practice that stands alone. There are two aspects to collaboration; first, teachers need to collaborate in order to develop transdisciplinary STEM experiences for students, or to support each other through a Professional Learning Community Model as they implement STEM learning. As Toolin (2004) identified, different factors such as education and experience play a role in the success of teachers in implementing STEM units. Through a collaborative approach, teachers can give and receive feedback to improve their practice and to navigate STEM-centered classroom management. Developing curriculum materials to support teachers can help us with implementation, but to develop any good materials to requires an iterative model with feedback from teachers and students, and must incorporate content standards in addition to STEM processes (Krajcik et al. 2008). A teacher community can support novice teachers, who tend to be more concerned with standardized testing and classroom routines (Toolin 2004). One last point to support teacher collaboration comes from O'Neill et al. (2012): Collaboration between experts in the field and teachers embarking/developing PBL pedagogy is important, because as students choose specific trajectories in their learning, they may be best helped by content experts, while the teachers facilitate. There is a growing collection of case studies that support teacher collaboration, including one focused on solid waste in middle school, where teacher collaboration for planning was vital. The teachers collaborated to plan a whole year STEM project about the local dump and brownfield incorporating all the subjects. Over the course of the project, the understanding about other standards and depth of knowledge was shared, and significant teamwork was important (Ewalt, K., Dortch B., and Russell, V. 2015).
With the teachers modeling collaboration, and navigating its pitfalls and successes, students can practice collaboration as well. The skills for collaboration must be directly taught (Vasquez et al. 2013) in the context of the STEM project. As Hoffer (2016) suggests, scientists communicate; teaching those communication skills is key. Project-Based Learning supports student collaboration in a number of ways, starting with the emphases on critique, revision, and reflection (armer, Mergendoller, & Boss 2015). The critique can come from teachers, peers, or other project partners, and students can revise process and products based on reflection of their critiques. As students work toward a product, they participate in formative assessment which allows them to modify direction and product. The last thread to consider in collaboration is the idea that students are collaborating with a teacher as a coach or mentor instead of an instructor (Juliani 2018). This level of collaboration is also important.