Before I get into the mis-management of the Phillies in the early- to mid-eighties, let me point you towards BaseballGraphs.com's explanation of Bill James' Win Shares. In short, a team's winning percentage is tied to the number of runs scored and runs allowed. And from there, it's only a "short" leap to tie individual performance to wins. Each hit or (hit prevented) is like a fraction of a run, which is a fraction of a win... Anyway, three win shares is equivalent to one win.
Onto the trade...
Between the 1981 and 1982 seasons the Phillies traded Ryne Sandberg (a prospect at the time) and an over the hill Larry Bowa to the Cubs for for Ivan DeJesus, and it was an unadulterated failure from the Phillies perspective.
After 1982, Ryno went on to put up 346 career Win Shares (according to Bill James) for the Cubbies, while Larry Bowa contributed 28. On the Phillies side, Ivan DeJesus was worth only 34 win shares to the Phillies before being traded again.
This time, the Phillies gave up DeJesus and Bill Campbell for the Cardinals' Dave Rucker. DeJesus and Campbell combined for 5 Win Shares for the Cardinals before being released, while Rucker gave the Phillies only 3.
So, the Phillies gave up 379 Win Shares and got only 37 in exchange. That's bad business.