Background. There is a growing need for valid shared decision-making (SDM) measures. We aimed to determine whether the items of extant SDM observer-based coding schemes assess the 4 key elements of... Show moreBackground. There is a growing need for valid shared decision-making (SDM) measures. We aimed to determine whether the items of extant SDM observer-based coding schemes assess the 4 key elements of SDM. Methods. Items of SDM coding schemes were extracted and categorized. Except for the 4 key elements of SDM (fostering choice awareness, informing about options, discussing patient preferences, and making a decision), (sub)categories were created inductively. Two researchers categorized items independently and in duplicate. Results. Five of 12 coding schemes assessed all 4 SDM elements. Seven schemes did not measure "fostering choice awareness," and 3 did not measure "discussing patient preferences." Seventy of 194 items (36%) could not be classified into one of the key SDM elements. Items assessing key SDM elements most often assessed "informing about options" (n = 57/124, 46%). Conclusion. Extant SDM coding schemes often do not assess all key SDM elements and have a strong focus on information provision while other crucial elements of SDM are underrepresented. Caution is therefore needed in reporting and interpreting the resulting SDM scores. Show less