EXHIBIT 11.1 DESKTOPDATA, INC. AND SUBSIDIARIES COMPUTATION OF NET EARNINGS PER SHARE (UNAUDITED) (in thousands, except per share data) Three Months Ended Nine Months Ended September 30, September 30, 1997 1996 1997 1996 ---- ---- ---- ---- Net income available for common stockholders $ 553 $ 1,202 $ 2,044 $ 3,065 ======== ======== ======== ======== Weighted average common shares outstanding 8,664 8,592 8,647 8,561 Common stock equivalents outstanding, pursuant to the treasury stock method 128 203 103 250 -------- -------- -------- -------- Weighted average number of common and common equivalent shares outstanding 8,792 8,795 8,750 8,811 -------- -------- -------- -------- Net income per common and common equivalent share $ 0.06 $ 0.14 $ 0.23 $ 0.35 ======== ======== ======== ======== 24