1 Exhibit 11.1 TRANSITION SYSTEMS, INC. COMPUTATION OF PRO FORMA EARNINGS PER SHARE For the three month period ended: December 31, 1996 December 30, 1995 ------------------ ------------------ Net income ............................................. $ 1,779,000 $ 1,179,000 Common stock outstanding .......................... 17,135,539 16,987,776 Common stock equivalents .......................... 3,390,401 3,630,730 Weighted average number of common shares........... and common equivalent shares outstanding ......... 20,525,940 20,618,506 Net income per share .............................. $ 0.09 $ 0.06