the Q score is a summary of the side, timing and amplitude of the asymmetry. 

• There is one Q score for forelimb and a combined Q score for hind limb (one for the pushoff component and one for the impact component). 
• Note that Q Scores have no +/- sign.  The limb and timing in stride cycle is described directly – i.e. L/R (for Left or Right) and Imp/Mid/Push (for Impact, Midstance, or Pushoff) in forelimb and Imp or Push for hind limb.  
• Q Scores do not assess variability. The user should still inspect lameness metric standard deviations (or the Trial AIDE statements) to understand the stride by stride consistency of asymmetry, which contributes to the overall evidence of lameness.

Can be considered the amplitude of total head movement asymmetry, taking into account both Diff Max and Diff Min of the head. 

As the side and timing of forelimb lameness is dependent upon both Diff Max Head and Diff Min Head, this single variable can be more easily used to estimate the overall level of forelimb lameness. 

Total Diff Head is the Vector Sum of the mean Diff Max and mean Diff Min values, and is calculated using Pythagorean Theorem (a² + b² = c²), where a is the value of Diff Max head, b is the value of Diff Min head, and c is Vector Sum. (a) is plotted on the X axis, (b) is plotted on the Y axis, and the hypotenuse that forms that triangle is the Vector Sum. Total Diff Head is indicated by the RED ray on the forelimb plot.

The Total Diff Head (Vector Sum) reference range is 0 to 8.5mm. The upper reference range value of 8.5 is derived from the VS calculation when Diff Max Head and Diff Min Head are at their upper reference range values of |6|.   6²+6²=VS²

Owner, horse, and trial specific data (including date, time and type of trial conducted).

Trial-to-trial variability = the variability of the mean lameness measure between two trials. I.e. is the measure repeatable? Trial-to-trial variability is assessed by comparing the lameness measures between two trials and whether they are within the 95% confidence intervals of repeatability.  If a particular measure in two back-to-back trials is not within the 95% CI, then that lameness is not stable.