MatchPoints versus IMPs
The difference between MatchPoints and IMPs is
simple enough. In MatchPoints, your score is put on
a list with everyone else's score. You get one
MatchPoint for every person you beat on this list, a
half a MatchPoint for everyone you TIE on that list.
Hence, if you do better than the 12 other people who
played the hand, you would get 12 MatchPoints. An
average result would be 6 MPs if 13 pairs play the
hand. On OKBridge, this is simply converted to a
percentage with 100% going to anyone who beats all
of the other pairs, 0% to anyone who registers the
worst score.
In International Match Points ("IMPs"), we
take the DIFFERENCE between the scores that you
and your opponents have achieved and convert that
difference to an arbitrary number of "IMPs"
according to this scale:
Difference in Raw Scores IMPs
0-10 0
20-40 1
50-80 2
90-120 3
130-160 4
170-210 5
220-260 6
270-310 7
320-360 8
370-420 9
430-490 10
500-590 11
600-740 12
750-890 13
900-1090 14
1100-1290 15
1300-1490 16
1500-1740 17
1750-1990 18
2000-2240 19
2250-2490 20
2500-2990 21
3000-3490 22
3500-3990 23
4000+ 24
IMPs were originally designed for team competition.
IMP PAIRS is simply an averaging of your opponents'
results before such a comparison takes place; you are
pitted against the "average opponent" when playing IMP
Pairs.
Playing IMPs, if you make 430 while others make
420, you have a raw score difference of a measly 10.
This is worth ZERO IMPs. Were you playing MatchPoints,
though, 430 would beat ALL the other pairs with their
420 scores; you would receive ALL the MatchPoints on
such a board. (This, by the way, explains the popularity
of No Trump contracts among MatchPoint players.)
Similarly, if EVERYONE ELSE scores +100 on a
hand, you will get all the MatchPoints with any score
above +100: +110 would get you the same fine result as
+1100 would!
At MatchPoints, then, you only need to beat the
score achieved by others who play the same hand. It
does not matter BY HOW MUCH you beat them.
At IMPs, though, it is not enough to beat the
others who hold the same hand as you. In order to
make headway, you must beat them by as much as
possible! If you score +110 as opposed to +100 you
will score a lot of MatchPoints, but a net difference
of (110 - 100 = ) 10 would net you ZERO IMPs. +1100
versus everyone else's +100, on the other hand, is
worth (1100 - 100 = ) 1000 net points, or a whopping
+14 IMPs.
How does this difference in scoring methods
affect your decisions at the table? Plenty!
At MatchPoints, making an overtrick in an
undoubled, non-vulnerable 4H while others make only
ten tricks means a "top" board (i.e. all the
MatchPoints available). But at IMPs, it means only
(450 - 420 = ) 30 points, or 1 measly IMP! With so
few IMPs at stake, this would be considered a "flat"
or "near-flat" board at IMPs. Many such hands which
are so exciting at MatchPoints ("Can you make that
critical extra trick?") are a total yawn at IMPs!
On the flip side, going down in 4H while
all others make 10 tricks is a "bottom" board, or
ZERO MatchPoints. At IMPs, though, you have just
lost (420 + 50 = ) 470 points in total, which
converts to a disastrous -10 IMPs.
From this we discern that, at IMPs, you
would NEVER risk the contract for an overtrick.
The risk (-10 IMPs here) far outweighs the gain
(1 IMP). At MATCHPOINTS, however, that overtrick
may mean the difference between a top and an so-so
result, so you MIGHT, if you see the chances as
better than 50%, put your contract at risk to
try for an overtrick (especially if you think
everyone will be in the same contract as you).
Similarly, on defence, you would always cash
the setting trick at IMPs to ensure defeating
the contract. But, at MatchPoints, an extra
undertrick might be worth the risk of NOT
cashing the setting trick in the hopes of
setting the contract TWO tricks!
"So," you might ask, "if going down in
a game which everyone else makes is a disaster at
both forms of the game, what's the difference?
Isn't it just one bad board?"
The difference is that at MatchPoints you
can recover by making an overtrick in 3D on the
very next board while everyone else makes only 9
tricks. At IMPs, this would only recover ONE of
the ten IMPs you lost going down in 4H earlier!
Because you need hands where big numbers are at
stake, it is much harder to recover from disasters
at IMPs BECAUSE THERE ARE FAR MORE "FLAT" OR
"NEAR-FLAT" BOARDS AT IMPs!
In MatchPoints, "the play is the thing". An
overtrick or an extra undertrick means EVERYTHING
if it distinguishes your score from everyone else's.
There are few "flat" boards at MatchPoints. In a
typical 24-board session at MatchPoints, you may
have 2 or 3 "flat" boards. In a typical 24-board
match at IMPs, you may have 12-18 such "flat" or
"push" boards. :(
At IMPs, bidding is paramount. Miss a slam
or a makeable game and you're in trouble. Squeezing
out an extra overtrick or extra undoubled undertrick
via careful play on the next hand will NOT recover
your loss.
The above distinction explains the expression:
"IMPs is for BIDDERS; MPs is for CARD-PLAYERS!"
It also explains why MatchPoints is a much more
intense game where EVERY board has equal importance.
A delicately bid and played 7NT contract will not
gain you any more or any fewer MatchPoints than the
lucky overtrick you made in 1C the hand earlier.
At IMPs, however, you can safely fall asleep during
the 1C hand--as long as you wake up for the 7NT one!
In this regard, by the way, IMPs is closer to Rubber
bridge than MatchPoints is.
Bottom line: At IMPs, the big "swing" hands
with a lot of points at stake (e.g. difficult games,
slams and doubled contracts) matter most. At
MatchPoints, all boards are equally important.
The area where the two games diverge most is
in competitive part score bidding. Consider this
situation: You have bid 3D, rather confident of
making. The vulnerable opponents compete to 3S.
You can't be 100% certain, but your instincts tell
you that 3S will likely go down one. Should you
double?
At IMPs, the difference between 3S down
one doubled versus undoubled is (200 - 100 = )
100, or THREE IMPs. If they make, though, the
difference is (730 - 140 = ) 590, or ELEVEN IMPs.
Hence, you'd better be VERY confident of 3S going
down before doubling it at IMPs! Otherwise, you
would do better to pass 3S. If it does go down
one, the board will be flat, since (110 - 100 = )
10 points means ZERO IMPs.
At MatchPoints, however, you were slated
for +110 in 3D, so +100 in 3S will NOT compensate
you. You may get a bottom board if everyone else
is allowed to collect +110 in 3D. Hence, to
"protect" your +110, you might double 3S and hope
to nip it one for +200 and a GREAT score at MPs.
Bottom line: save those close doubles for
MatchPoints, not IMPs!
At MatchPoints, you will often strain to
balance the enemy into an unmakeable contract.
Nothing does your game better than pushing the
opponents to 3H and collecting +50 while
everyone else is -110 against 2H. If balancing
against their 2H risks the odd -800 because of
a trump stack against you, so be it. As long
as you collect more +50s than -800s you'll do
fine in the long run at MatchPoints.
At IMPs, though, those -800s had better
be FAR fewer. Getting +50 versus -110 is worth
(50 + 110 = 160) FOUR IMPs. -800 versus
-110 loses (800 - 110 = 690) TWELVE IMPs,
and such disasters are harder to recover from,
with fewer decisive boards at IMPs than at
MatchPoints. :(
Bottom line: save your balancing heroics
and aggressive part score competing for when
you're playing MatchPoints, not IMPs!
Let's take another scenario. They have
bid 4H, vulnerable. You figure that they have
a better-than-even chance of making it. Your
side, on the other hand, can bid 4S, get
doubled, and go down -500, 120 points better
than you will spit up for 4H if it makes.
Should you sacrifice in 4S, then?
At MatchPoints, the answer is YES.
If they do make 4H you are have improved
your score from -620 to -500. Yes, if 4H
goes down, you -500 will not look good
opposite everyone else's +100. But as
long as 4H has a better than 50% chance
of making, you will gain more often than
you will lose IN THE LONG RUN.
At IMPs, the answer not so clear.
4S will only improve your score by
(620 - 500 = 120) THREE IMPs. If, on
the other hand, 4H goes down one, you
will have foregone the +100 for -500,
a 600 point difference for MINUS TWELVE
IMPs. Since your sacrifice has to be
"correct" (i.e. 4H has to make) 4 times
to 1 for those 3 IMPs to equal the 12 IMPs
you might be missing, 4H should have an 80%
or better chance of making before you should
sacrifice against it! At MatchPoints, your
sacrifice only had to be right 51% of the
time to pay off in the long run!
Bottom Line: At MatchPoints,
sacrifice against anything the opponents
bid confidently. At IMPs, sacrifice only
against those contracts which are
underwritten by Lloyds of London! :)
And that, in a nutshell, is the
difference between IMPs and MatchPoints.
