Ordinal variable is a measurement which allows a sample of the individuals to be ranked with respect to some characteristic but where differences at different points of the scale are not essentially equivalent. For instance, anxiety may be rated on a scale 'mild', 'none', 'moderate' and 'severe', with values 0,1,2,3, being used to label the categories. A patient with anxiety score of one could be ranked as less anxious than one given a score of three, but patients with scores 0 and 2 do not necessarily have the similar difference in anxiety as patients having the scores of 1 and 3.