... A wide range of measurement tools have been used to quantify comfort, including simple dichotomous responses [11,12,29,94], ranking footwear conditions in order of preference [14, 31-33, 36, 47, 48, 52, 60, 63-65, 76, 77, 79, 81], 4-point [42,80], 5-point [37,40,45,58,70,76,97], 6-point [59], 7-point [47,64,79,87], 9-point [57] and 12-point [41] Likert scales, 10-point numerical rating scales [43,78], and 100 mm [15, 16, 18-21, 27, 28, 30, 35, 39, 48, 49, 53, 56, 63-65, 67, 68, 71, 73, 74, 77, 79, 82, 85, 89, 90, 93, 99, 104, 105], 150 mm [22,25,26,36,46,50,55,61,62,66,69,75,83,84,98,100] and 170 mm [44] visual analog scales. The anchor statements indicating the lowest possible comfort score included 'not comfortable at all' [19-22, 25, 26, 30, 39, 49, 50, 53, 55, 56, 61-65, 73, 79, 82-85, 89, 93], 'very uncomfortable' [27,28,40,41,45,46,58,68,74,78,79,98], 'least comfortable' [44,76,80,90], 'extremely uncomfortable' [48,59,89], 'not comfortable' [71,75], 'not at all comfortable' [15,18], 'not acceptable' [37,70], 'totally disagree' [10], 'least comfortable imaginable' [35], 'not satisfactory' [42], 'very bad comfort' [43], 'very, very low' [47], 'minimum comfort' [69], 'maximal pain/discomfort' [99], 'not very comfortable' [100], 'completely uncomfortable' [104], 'extremely bad' [57] and 'unbearable discomfort' [87]. The anchor statements indicating the highest possible comfort score included 'most comfortable imaginable' [19-22, 25, 26, 30, 35, 39, 46, 50, 53, 56, 61, 63, 65, 73, 79, 82-84], 'very comfortable' [18,27,28,40,41,49,58,68,71,74,75,78,79,98,100], 'most comfortable' [44,55,62,76,80,85,90], 'extremely comfortable' [48,59,87], 'just right' [37,70], 'totally agree' [10], 'very much' [15], 'excellent' [42], 'very good comfort' [43], 'not at all uncomfortable' [45], 'very, very high' [47], 'maximum comfort' [69], 'maximal comfortable' [64], 'no pain/discomfort' [99], 'completely comfortable' [104], 'most conceivable comfort' [93] and 'extremely good' [57]. ...