Table 1. Online sources for extracting monthly civilian casualties, monthly attacks on healthcare facilities, and monthly Syrian refugee counts.

Online Sources	Data Type	Duration of Documentation	Description of Documentation	Verification Methodology
Violations Documentation Center (VDC)[39]	Civilian Casualties	Mar. 2011 to present	1. Gather initial information from hospital registries, morgues, relatives or media sources 2. Confirm initial report with videos or photographs 3. Key information missing is investigated until published44	Three-stage verification process: initial reports, video/photo evidence, investigation until confirmed
Physicians for Human Rights (PHR)[38]	Attacks on Healthcare Facilities*	Mar. 2011 onwards	Uses social media, publications and field sources to identify attacks before publishing attacks on healthcare facilities and personnel on their online platform	Verification by at least two independent sources before publication of confirmed attacks
United Nations High Commissioner for Refugees (UNHCR)[45]	Registered Syrian Refugees	Mar. 2011 onwards	Government agencies, UNHCR field offices and NGOs contribute to UNHCR’s online database for cumulative refugee counts	Verification by three independent sources

*Attacks on healthcare facilities are defined as a violent assault (e.g. bombing, shelling, artillery, car bombs, shooting, arson, or attack by armed personnel) on a hospital, clinic, medical center, pharmacy, dispensary or field hospital.[21]