Mathematical notation for formulating a rank score
Here is my solution to the problem. I am posting it here in case anyone else come up with the same idea but did not know how to formulate it in mathematical notation!


  $$ \psi_i = \sum_{i=1}^9 S_i $$
  
  where $S_i$ is the score function and defined as:
  
  $$
S_i = \cases{
  0 &amp; \text{if $\theta(x_i) &lt; Q_1$ or $\theta(x_i) = $ benign/neutral} \\
  0.5 &amp; \text{if $Q_1 \leq \theta(x_i) &lt; Q_3$ or $\theta(x_i) = $ possibly damaging/uncertain} \\
  1 &amp; \text{if $\theta(x_i) \geq Q_3$ or $\theta(x_i) = $ damaging}
}
$$
  
  The $\theta(x_i)$ is the pathogenicity or conservation score for variant $x$ as defined by model $i$ and $Q$ denotes the quartile range for scores from M-CAP, CADD, GERP and Phylop models.