Table 4.

Stages of receipt and integration of feedback during the development of QoE-SPEO and main innovations introduced.

Stage	Feedback	Main innovations
1	Two rounds of feedback on QoE-SPEO v.1 received from two WHO experts and five individual experts on systematic review methods and integrated in QoE-SPEO v.2	- Adopted and/or revised steps and components from existing tools - Developed a new step - Developed new components - Introduced concepts, terms and examples from occupational health and safety
2	First round of pilot testing on QoE-SPEO v.2, feedback received from ten pilot testers and integrated in QoE-SPEO v.3	- Made minor editorial changes
3	Second round of pilot testing on QoE-SPEO v.3 received from 20 individual experts in occupational health, occupational safety, and/or exposure science that applied QoE-SPEO v.3 in a systematic review of prevalence studies for the WHO/ILO Joint Estimates and integrated QoE-SPEO v.4	- Reviewed and improved the concept, definition and term for “expected heterogeneity” - Refined considerations and criteria for some downgrade domains - Added definitions of quality of evidence ratings