Table 1.

Core Outcome Set-Standards for Development recommendations as applied to both COSMIC: Intervention and COSMIC: Observation COS

Domain	Standard	Methodology	COSMIC: Intervention	COSMIC: Observation
Scope specification	1	The research or practice setting(s) in which the COS is to be applied.	Later phase clinical effectiveness trials that will inform clinical decision-making.	Clinical studies of incidental and untreated intracranial meningioma that will inform clinical decision-making.
	2	The health condition(s) covered by the COS.	Sporadic intracranial meningioma requiring intervention, including multiple meningioma and those with SMARCE1-related familial meningioma, but excluding NF2-associated meningioma.	Incidental and untreated intracranial meningioma (including those which are minimally symptomatic).
	3	The population(s) covered by the COS.	Human adults aged 18 or above.	Human adults aged 18 or above.
	4	The intervention(s) covered by the COS.	Interventions including surgical resection, radiotherapy, stereotactic radiosurgery, chemotherapy, perioperative care and supportive treatments; any of which may be in isolation or in combination with each other.	Active monitoring only as an intervention, but not treatment for an intracranial meningioma.
Stakeholders involved	5	Those who will use the COS in research.	Clinical trialists who manage patients with intracranial meningioma. They are included in standard 6.	Clinical trialists who manage patients with intracranial meningioma. They are included in standard 6.
	6	Healthcare professionals with experience of patients with the condition.	This will include clinicians from multiple subspecialties and non-clinician healthcare professionals with active involvement in the care of patients with intracranial meningioma.	This will include clinicians from multiple subspecialties and non-clinician healthcare professionals with active involvement in the care of patients with intracranial meningioma.
	7	Patients with the condition or their representatives.	Patients with a diagnosis of intracranial meningioma who have received treatment will be included, along with relatives and carers of such patients.	Patients with a diagnosis of incidental intracranial meningioma who have not received treatment will be included, along with relatives and carers of such patients.
Consensus process	8	The initial list of outcomes considered both healthcare professionals and patients’ views.	A trial registry search and systematic literature review of intracranial meningioma trial outcomes will consider healthcare professionals’ views, while patient research partner input and published semistructured interviews with patients will consider patients’ views.	A trial registry search and systematic literature review of clinical studies of incidental and untreated intracranial meningioma will consider healthcare professionals’ views, while patient research partner input and published semistructured interviews with patients will consider patients’ views.
	9	A scoring process and consensus definition were described a priori.	Described in the ‘Scoring’ and ‘Analysis’ sections of this protocol.	Described in the ‘Scoring’ and ‘Analysis’ sections of this protocol.
	10	Criteria for including/dropping/adding outcomes were described a priori.	Described in the ‘Analysis’ section of this protocol.	Described in the ‘Analysis’ section of this protocol.
	11	Care was taken to avoid ambiguity of language used in the list of outcomes.	Both study content and study materials will use plain language summaries and clinical explanations where necessary. All materials will be reviewed with patient research partners and pilot tested with patients and healthcare professionals.	Both study content and study materials will use plain language summaries and clinical explanations where necessary. All materials will be reviewed with patient research partners and pilot tested with patients and healthcare professionals.

COS, core outcome set; NF2, neurofibromatosis type 2.