## 2 Materials and Methods  
To understand the methodology of this work, it is useful to look first at the context given by the CreaSTEAM project; starting from this point, the process can then be split into the development of a corpus of STEAM diversity initiatives and its review. To deploy STEAM-Labs to improve diversity gaps, the CreaSTEAM project focuses on two concrete objectives: mapping STEAM diversity initiatives (IO1) and developing frameworks for implementing STEAM-Labs (IO2). These will be accomplished through the following phases:  
* Phase 1, initiative mapping: Catalog existing diversity-focused groups, companies, and organizations to look for and analyze best practices to design the STEAM-Lab curriculum. Phase 1 is this paper's focus. * Phase 2, STEAM-Lab design: Find key educational components that should be present in the labs, provide training for teachers who will be in the labs, and formalize the STEAM-Lab definition. * Phase 3, pilot: Roll out the program in participating schools (which include partner educational associations, public schools, and additional associated schools in Germany, Italy, Spain, and Turkey). * Phase 4, evaluation: Simultaneously with Phase 3, record data about the roll-out, including individual student profile evaluations. * Phase 5, integration: Analyze the data from Phase 4 and finalize a STEAM-Lab methodology. To develop the corpus of initiatives, we followed PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses), a widely accepted process for objectively screening sources that will be used in systematic reviews [17; 18]. We applied the following inclusion criteria:  
* IC1: Initiative is focused on STEAM or diversity AND
* IC2: Initiative webpage has enough information in English or Spanish to gather data AND
* IC3: Initiative webpage is functional and securely accessible and pertains to the initiative AND
* IC4: Initiative is not better classified as another institution (such as a school or museum) On the other hand, we formulated the following exclusion criteria:
* EC1: Initiative is not focused on STEAM or diversity OR
* EC2: Initiative webpage does not have enough information in English or Spanish to gather data OR
* EC3: Initiative webpage does not work, is not securely accessible, or does not pertain to the initiative OR
* EC4: Initiative is better classified as another institution  
Additionally, because grey literature does not have embedded quality controls, the inclusion conditions were also used as the quality criteria. The search for initiatives was carried out in different phases, in an ad hoc manner by many different participating universities and schools located in Germany, Italy, Spain, and Turkey. The searches occurred from February 2021 to May 2022 and gathered data from the internet, using Google, Bing, and DuckDuckGo web browsers. Search strings were made by combining terms from the following groups:  
* Group 1 (geographic region): \"Germany\", \"Italy\", \"Spain\", \"Turkey\", \"Europe\", United States\"
* Group 2 (content area): \"Science\", \"Technology\", \"Engineering\", \"Art\", \"Math\", \"STEAM\", \"STEM\"
* Group 3 (diversity target area): \"Diversity\", \"Gender\", \"Women\", \"Girls\", \"Economic\", \"Immigration\", \"Disability\", \"Different ability\", \"Race\", \"Under-represented\"
* Group 4 (additional): \"Initiative\", \"Education\"  
To rapidly eliminate obviously irrelevant results returned by the search engines, EC1 was applied during the search process, before the PRISMA screening. Likewise, duplicates were removed before the formal screening process began. To avoid inconsistent labeling of the initiatives, the lead author screened all initiatives according to ECs 2, 3, and 4, and confirmed or updated the previously recorded information on each initiative's country, organizational type, activities, status (active or not), founding year, STEAM content areas, and diversity target areas (gender, economic, different ability, and immigration status).