Two telephone meetings have been held among the partners to work out a strategic plan for WP4 (see Figure). Tasks 4.1, 4.6 and 4.8 have been started. The main task of WP4 was defined as the development of a guidance for instrument selection for COS (task 4.6.2). A Delphiprocess will be performed to achieve consensus on the relevant components of this “how to measure” guideline (task 4.6.1). As input for this Delphi process a search strategy is being developed by a research librarian to identify relevant papers that describe methodology for the selection of measurement instruments for outcomes included in a COS (task 4.1). The search will be performed in the Cochrane database of systematic reviews, Cochrane database of methodology reviews, Medline, CINAHL, Embase, and PsycINFO. In addition, apreliminary list of relevant stakeholders have been drafted and will be augmented using a “snowball sampling” approach. Stakeholders will be invited to participate in the Delphi process. A preliminary version of a “how to measure” workshop (task 4.8) have been drafted. This workshop will be given at the 3rd COMET meeting June 2013.