# Monopoly: Strategy in trading --how do I compute the expected value of a trade?

I love playing Monopoly with my friends and I'm known for giving extra money or trading a cheaper property with a more expensive one and even paying some amount on top of it.

Obvioulsy I love the smaller cards, as I can buy more houses in a short amount of time and earn more money in the long run. This strategy did work really well most of the time, but lately I'm paying too much for those properties.

I wonder if there is a quick method to figure out when a trade gives me positive expected value (+ev).

• How do you know you're paying too much? Could it be that your friends are on to your strategy? ;-) – Kristo Nov 16 '10 at 1:08
• in the last game my friend used that money to build houses on his now complete property, and I lost ;) I guess I did a bad deal that day – Sven Nov 16 '10 at 7:55

I don't think there is a quick method, but there are a few simple rules to consider when trading your cards.

1) How much is the card worth to you. Therefore, what can you do with the money you gain as opposed to what could you do with the card you are selling

2) How much is the card worth to your opponent. If you are selling a card that allows an opponent to complete a row, you have to understand how likely they are to build houses/hotels and the likelihood of it affecting your game plan further into the game.

3) If selling to an opponent who doesn't really need the card, consider the likelihood of them selling the card on, and the impact this will have, as per point 2.

For buying a card, the rules are pretty much the same as above, but inverse. You always need to weigh up the benefits you gain as opposed to what your opponent may gain, and think several moves ahead.

Also, take a look at this thread about the best ROI for properties. Which property group colour gives the best ROI , undeveloped or fully developed, in Monopoly?. This will help you to calculate the real values of the properties in the game.

I actually do have a couple of quick methods that I use when offered a trade, and the one I use depends on the stage of the game we're in.

## Early game

The first few trips around the board. No one has a monopoly, most color groups have 1-3 properties available.

• Do the properties contribute toward possible monopolies equally? (If she has an orange, I'm not trading her an orange unless I get a second property in another color in return. This applies to railroads as well: I'm not giving someone a second railroad for a property in a "new" color, for the most part.) Note: even if they do, make sure you keep an eye on the third property in each group. This can be especially important if additional opponents are prone to completing monopolies through trade, even if it hurts them to do so.
• If that's not applicable, are the properties roughly of equal total value? (I'm not giving him Boardwalk for Indiana Avenue.)
• If they're not roughly equal, can money be added to make them so? (A rough estimate is all you need; early in the game, it's hard to tell which properties are key.)

If it's "no" to all three, then I decline the trade. Otherwise, it might be worth it ... getting a chance at an early monopoly or a set of railroads can make a big difference early on. \$200 isn't nearly as big of a deal when you have \$4000 in assets as it is when you have \$1900.

## Mid to late game

A good number of properties have been purchased; one or more opponents may have monopolies, both utilities, or all four railroads.

• Does everyone but me have a monopoly? Then yes, I make the trade. You simply can't build up enough cash without a monopoly in the late stages. Conversely, if everyone but my opponent has a monopoly, then no, you don't get one.
• If there are several possible monopolies left, and we're setting each other up, are the monopolies roughly equivalent? If not, then no trade. (Remember, light blue, orange, and dark blue are your targets. Don't give one unless you get one. Greens aren't really an asset unless you can afford to build them up immediately and still have an emergency fund. While they're a good initial value, Baltic/Mediterranean start to lose value once your opponents can pick up 2x to 8x that rent in one roll.)
• If it's not going to be for mutual monopolies, am I helping out my opponent too much? Keep in mind that you have no control over your opponents' trades: picking up Boardwalk for New York Avenue seems like a decent late-game trade, but you may not get Park Place out of the person who has it, and if someone else passes the last orange to your trading partner, suddenly they have a new monopoly and you've got nothing.

How successful is that? It's hard to say, given the luck involved and the difference in opponents you'll face. Even with that handy ROI table next to you, you still can't be sure you'll win more games in the long run, and it's always possible that developing a reputation as a shrewd trader will hurt you within your group: people may actually trade with you less often, even if your trades help your opponents as well, just because you're good at it! But that philosophy seems to work for me.

Basically, I like to trade when I have a lot of money. I don't like to trade when I don't have money (and my opponents do). Unless you're trading for Baltic and Mediterranean, it's not a question of who has the better properties, but who can develop them fastest. (And I once lost a game landing on a hotel on Baltic, even though I had the maroon and green groups.)

For this reason, I don't like to give money in trade. Much more inclined to accept money as the "difference" in a trade of say, the dark blues for the maroons. But once I traded the greens for the maroons "straight up" and won, because I had over \$1,000, and my main opponent (in a three way game) was almost broke.

• That trade wasn't a bad one anyway. Although the maroons don't have a good ROI (with the exception of St. Charles), the greens are even worse: they're the most expensive to develop (because there are three as opposed to just Park Place/Boardwalk) and have no cards that force an opponent to land there. – Dave DuPlantis Jun 24 '11 at 15:45
• @dave: One opponent had the dark purples (and four houses on each). The other had two out of three oranges (and would get later the third). I had the most money and was desperate to get ANY monopoly, because I had none. They (brother and sister) laughed at me. Until I won. – Tom Au Jun 24 '11 at 16:45
• That actually reminds me of something that I consider when a trade offer is made ... thanks for jogging my memory! – Dave DuPlantis Jun 24 '11 at 17:25

It may not be a quick method. But for a full answer to property expected value, I recommend the following book: Winning Monopoly

This book has includes the results of doing the math for the expected value of the different properites in key stages of the game. The book is not just tables, but includes solid explainations and good rules of thumb for evaluating most decisions in the game. Some key factors to consider in evaluating each side of a trade are: 1. Having a winning Monopoly that can bankrupt an opponent(s). Including ownership and the ability to buy improvements. 2. Number of turns left to play in the game, if a time limit is explicity or implictly in place. 3. Likelihood of getting rent in addition to amount of rent.

Understanding the concepts in the book and the data presented really helps estimate the value of each property to each side of a trade, in the current game situation.

• Can you summarize the important bits on trading from that book? I can't tell if this is a good answer or not, because I'd have to buy the book to find out. – PotatoEngineer Sep 3 '13 at 18:18