The term methodologist or methodological expert is not clearly defined. In the context of evidence-35 based health care and in particular in knowledge synthesis, an expert is someone with excellence in 36 synthesizing evidence. To achieve such expertise, a lot of different skills need to be acquired along 37 with experience in multiple projects. However, the concept of knowledge synthesis should not only 38 be limited to performing different types of reviews (e.g. systematic, scoping, and rapid); it also 39 includes questions of how to make evidence available, and how to communicate findings to the 40 public and decision-makers. All of this is currently extremely important. We need to know where to 41 identify new studies as fast as possible. Based on them, reviews are conducted, whereby many of 42 them may follow methods developed for rapid reviews, which may reduce certainty in their 43 findings. All needs to be communicated fast and to the appropriate decision-makers. The huge 44 challenge for methodological experts is that given the current circumstances, it will frequently not 45 be possible to use the optimal methods for knowledge synthesis, and to balance challenging trade-46 off between optimal methodology and timely results. 47 48
Several key aspects define the new context of action for clinical decision-making in the ongoing 50 pandemic. Firstly, clinicians lack time to critically assess the quality of the evidence that is 51 appearing about COVID-2019; on April 14, 2020 there were 5,362 articles stored in the WHO 52 database (based on searches up to April 9, 2020) [3]. Secondly, although it seems that the scope of 53 research is very narrow, since it addresses evidence on a well-defined core topic (COVID-2019) and 54 on a well-defined time frame, available publications address very different aspects of the problem 55 and are presented in multiple formats, some of which (letters, opinion, news, comments) would be 56 setting up an initiative called Evidence Network to support Decision-making (COVID-END) [11] . 88
This network aims to coordinate and reduce duplication in efforts among all types of researchers, 89 including in the evidence-synthesis, technology assessment and guideline-development 90 communities that have long track records of supporting decision-makers locally, nationally and 91
internationally. 92
There are other COVID-19 databases; these are probably the most prominent [12] . However, these 93 platforms are very similar. Each of these organizations is investing massive human resources to 94 develop and maintain these evidence maps, while they could be all working together and prevent 95 overlaps and duplications. Furthermore, these resources do not offer appraisal of methodological 96 quality of evidence. When clinicians start searching evidence on a certain topic in these collections, 97 they will get a list of articles, but they will not know whether this evidence is good, or good enough 98 in terms of methodological quality. Articles presented to clinicians could be useless examples of 99 research waste. Furthermore, these databases could be more transparent in terms of their methods. 100
In some cases it is not well described which databases and journals are searched. In the WHO 101 database of COVID-19 publications it is unclear what is "non-conventional" information source and 102 the searching option by year is not optimal, as it would be much more helpful to allow filtering in 103 line with different article types and exact publication dates. Additionally, most of these resources are 104 in English. An updated interface of the WHO collection now includes different language options, 105 experienced researchers have started curating the records by deeply tagging every study using an ad 12, 2020], there were 2,577 abstracts and 14,309 tags with up to 32 tags/abstract. The complexity of 119 such granular tagging will serve to: i) deploy a new free open tag-based searchable database to be 120 used by any researcher worldwide [14] ; ii) to locally post a weekly updated executive summary 121 about the amount of new evidence, by topics, fields, and study designs, which will include a 122 methodological evaluation and any concerns about the confidence of their results; iii) to weekly 123 publish a free available podcast with some contents of the executive summary to facilitate all 124 clinicians to consume our analyses whenever and wherever they can/want; iv) to communicate daily 125 with users via social messaging apps. For the latter, we have created an intra-hospital WhatsApp 126 team, 'the COVID-evidence team', involving clinicians (Intensive Care, Internal Medicine, 127
Pneumology, Infectious Diseases, and Epidemiology and Healthcare workers) and methodologists. 128
The team communicates via WhatsApp chat with end-users. The chat enables end-users to propose 129 new questions in a PICO format for us to search scientific answers using our COVID-evidence web 130
service. Methodology quality assessment of primary or secondary included studies will be 131 performed on demand to answer every specific PICO question sent by clinicians. Final reports will 132 be uploaded to the platform to share our analysis with the scientific community. Finally, a contact 133 form is available on the web page for those methodologists interested in collaborating on this 134 project. 135 136
The scenario for evidence-based medicine has changed. Government agencies, institutions, and 138 research groups keep working harder to produce summaries and quality assessments documents of 139 existing evidence. However, we believe that there is room for specialists in research methodology to 140 provide our best knowledge and expertise, without forgetting the rigor of evidence-based medicine 141 research standards, to support clinicians who are making decisions on the front line. In this duality 142 of interest, we believe that new strategies for new times will be required to address it. The example 143 of COVID-evidence project in Spain indicates that collaboration of clinicians and methodologists, 144
can produce evidence-synthesis with assessment of methodological quality 'on demand' and based 145 on 'a living dialogue', in a non-English language, that the end-users use and appreciate. We hope 146 that our love for the best methodological standards will not paralyze us and prevent us to offer 147 clinicians our support just in the right time. • Research community has responded rapidly, and thousands of articles have been published already in scholarly journals, making it difficult for clinicians to sift through the evidence and find answers.
• Methodologist researchers and relevant international organizations have addressed the pandemic immediately. However, these efforts are hindered with avoidable problems and massive duplication of effort.
• We believe that research methodologists can be very useful now to clinicians. The COVIDevidence project can be an example of how to establish a living dialogue of methodologists and clinicians to fight COVID-19 pandemic.