RUNS= (HITS+WALKS)*(TOTAL BASES)/(AT BATS + WALKS)
James tinkered with with the Runs Created formula constantly before his "retirement" in 1988, and continues updating it to this day. The basic theory behind the runs created formula is an On Base (HITS+WALKS) Factor multiplied by an advancement factor (Total Bases) divided by opportunity (AT BATS+WALKS). In recent years James has changed the formula and the way the two factors and opportunity combine.
The version I use is the most similiar to James' most recent work, but altered to use the data I have available.
The formula used has three factors: A (On Base), B (Advancement), C(Opportunity)
A=Hits+Walks+Hit by Pitch-Caught Stealing
B=Total Bases+.26*(Walks+Hit by Pitch)+.53*(Sacrifice Flies+Sacrifice Hits)+.64*(Stolen Bases)-.03*(Strikeouts)
C=At Bats+Walks+Hit by Pitch+Sacrifice Flies+Sacrifice Hits
James also changed the construction of the formula to measure "lineup effect" (The Big Bad Baseball Annual has done some interesting work to discover what this does), the factors are now combined:
RUNS CREATED = ((A+2.4*C)*(B+3*C))/(9*C) -0.9*C
Runs created remains still remains popular despite its tendancy to overevaluate players with high onbase and slugging averages (i.e. Frank Thomas pre 1998).
1B 2B 3B HR HBP+BB-IBB IBB SB CS .5 .72 1.04 1.44 .34 .25 .18 -.32 AB-H-K K GIDP SF SH -.09 -.098 -.37 .37 .04I up the value of Strikeouts to -.1, Other Batting outs to -.0095 and ignore GIDP, because I don't have access to the information.
A (very) short list of other measures used by other people:
There are many more sabermetric methods and tools available to help anyone attempt to answer. If you are interested there are many links I can suggest.