FWIW...


a quik way to convert from decimal (D) to american-style (A) odds

If D>=2.000 A=(D-1)*100 [ie. subtract one from the decimal odds and move the decimal two places to the right]

If D < 2.000 A= -100/(D-1) [ divide 100 by "one less than the decimal odds" and put a negative sign in front]

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Again FWIW, one extremely useful feature of the Decimal format is that

1/D ["the reciprocal of the decimal odds"] tell us the implied win% of this bet

eg. for plays at -130 --> D=1.7692, so probability of the bet winning, implied by the book is 56.53% [1/(1.7692)]

meaning any win percentage above 56.53% on any number of -130 bets would beat the book, any win% less than that would lose.

(my two cents...actually 6 sbr-points...worth for the day)

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So if you're looking for value, estimate as accurately as possible the % of times the event you like would occur if it could be played many times in identical "parallel universes"....then take the reciprocal of your estimated win%...that's the odds that you'd expect to "break even" with...and look for an "edge" =a book's decimal odds being considerably higher than what you just calculated...

<(your perceived win%)/(book's implied win%)-1> or equivalently [(book's decimal odds)/("your" perceived decimal odds) - 1]** tells you your expected yield if you took that bet repeatedly

btw, the %-edge that you reckon you have on this play at this odds is roughly (but not exactly...but close enough for my purposes here) equivalent to the full "kelly criterion" optimum bet-size..a bet with a bigger % edge=>a bigger bet...so when someone savvy like LTA puts on a 1.5x or 2x play you can bet his perceived edge is 50% or 100% larger than his usual play (eg. 4.5% or 6% perceived edge vs his usual 3%-ish edge for regular plays)...whether quantified explicitly like this or not, it is such considerations that constitute differing levels of "confidence"

Example time... you cap a game to win 60% of the time (ie. "your" implied break-even odds are thus 1/0.60=1.6667 or -150...the book odds are 1.7692 or -130 (ie. the book "figures" the probability to be 56.53%)...your perceived edge can easily be calculated as the ratio of the win% 60/56.53 less 1= a very attractive 6.1% (or alternatively, and even more handily...which is what I like about decimal odds format by 1.7692/1.6667).

side note: a full-kelly bettor would pound this at just about 6% bank (the optimal full-kelly percentage is under most circumstances very nearly the same thing as the edge that can be calculated as a simple ratio (of win%'s or of decimal odds as above)...a more conservative long-term more "crash-resistant" approach is a fraction of this edge...eg. a half-kelly bet would be 3%of bank, quarter-kelly 1.5% of the bank for this bet

nuff said for 6 measly betpoints (30c in "street value)...lol