1 Exhibit 11.1 TRANSITION SYSTEMS, INC. Computation of Earnings per Share For the year ended September 30, 1997 Weighted average shares outstanding: Common stock outstanding (1) 17,432,479 Common stock equivalent 3,125,504 Pro forma weighted average number of common shares and common equivalent shares outstanding 20,557,983 ---------- Net income: Net income before extraordinary item 5,319,079 Extraordinary item -- Net income 5,319,079 Net income allocable to common stockholders 5,319,079 Earnings per share: Net income before extraordinary item 0.26 Extraordinary item -- Net income 0.26 Net income allocable to common stockholders 0.26 For the year ended September 30, 1996 Weighted average shares outstanding: Common stock outstanding (1) 13,214,432 Common stock equivalent 3,757,289 Pro forma weighted average number of common shares and common equivalent shares outstanding 16,971,721 ---------- Net income: Net income before extraordinary item 6,287,256 Extraordinary item (2,148,697) Net income 4,138,559 Net income allocable to common stockholders 3,545,083 Earnings per share: Net income before extraordinary item 0.37 Extraordinary item (0.13) Net income 0.24 Net income allocable to common stockholders 0.21 (1) Gives effect to the Recapitalization. See Note 9 of Notes to the Consolidated Financial Statements.