Sports betting is exciting. A goal in the last minute can make you win or lose. Arbitrage betting is also exciting, but in a very different way. Rush occurs during the detection and placing of bets rather than while waiting for the event outcome. Anyway, we love betting and we are proud of our ability to make profit. How much profit and how do we achieve it? Could we do it better? As in any business (professional bettors and surebettors are businessmen), we need good information to tell.

Most recreational bettors lose money. In fact, they lose a lot of money. They bet following their heart. They try to recover by betting more money in an impulsive way. And someday they hit a correct score bet with odds greater than 10 and they celebrate and forget previous losses. In fact, if you ask them how they are doing they don’t even know if they win or lose in the long term (although according to several analysts, between 90% and 98% sports bettors are losers). If they had detailed information would they continue betting? (Maybe yes…)

But professional bettors – those who take betting as an investment or a job – they must know if they win. And how much. And how, when and where. Assuming you are in this group, can you tell…

• How much did you bet?
• How much did you win?
• How many bets?
• Your average and maximum stake?
• Your average and maximum win? And loss?
• How much did you invest and cash out?
• Your ROI and yield?
• Your average arbitrage? Your maximum arbitrage?
• Your total balance? Your balance on each bookmaker?
• Your stake, return, profit or loss per bookmaker?
• The bonuses you received? The fees you paid?
• Which sports you bet on? Which markets? Which competitions or countries?
• Which sport is most profitable? And which market, competition or bookmaker?
• How many open bets do you have? Where are they?

You should.

And all these questions could be combined, and asked for a specific period of time – last week, last month, year to date, since the beginnings of time.

To answer these and many other questions we need to keep records.

Record keeping – tools

Record keeping can be done using different tools.

• No record keeping. You can always use the historical data bookmakers provide. This is a good option only if you use a few bookmakers, but it’s not useful for arbitrage bettors who use 20, 30 or more bookmakers.

• Pen and paper. Maybe it’s better than nothing, but not so much. You can keep track of all your bets on paper, but it will be almost unusable for reports and statistical information.

• Electronic documents (word processors). While this is much better than using only pen and paper, analytical possibilities are still very limited. At least, searching for specific bets will be easier and you could transfer this information to other formats later with some work.

• Electronic spreadsheets. Now you are taking it seriously. Spreadsheets are a good tool to keep your bet record. Of course, you need a well-designed record to make it easier entering information, minimise errors and enable analysis. We’ll talk about this in a moment.

• Applications and databases. This is the top-stage. Applications have all the advantages of spreadsheets and can also provide a lot more possibilities, depending on their quality.

Record keeping – what to record

It would be nice to have enough information to answer all those previous questions and more. But it is also very probable that the more information you record, the more effort it will take. You need to balance the effort and the benefits. So, what to record?

The information you need to perform analysis and answer the initial questions include, for each bet:

• Bookmaker
• Date and time
• Stake and currency
• Odds
• Return and profit/loss
• Sport, country and competition
• Market

And you also need other information, like money transfers, just to mention one.

Record keeping – excel approach (introduction)

Let’s design an Excel sure bet tracker!

First of all, we must define the main entities we will use when recording bets, because it’s not only about bets. We suggest defining these main entities: bookmakers, sports, markets, countries, currencies, transaction types and bet types. Of course, you do not need a detailed entity definition for each one, but it’s good to treat them as entities with a key (or code) and the remaining information, and use references to each one on your bets. That’s a basic database design best-practice that will minimise errors and make maintenance easier.

What about bets? Besides these entities (master records) we must define bets (transactional records). We suggest defining bets and transactions so that we can also track deposits, bonuses, fees, etc. And if we want to track surebets, we must record information about which bets belong to each surebet.

What should we include for each entity? We can include as much or as little as we like. In our next article we will provide a simple but complete Excel design that will allow us to analyse:

• Money invested and cashed out
• Bonuses received
• Number of bets
• Total stake, return and profit
• Open bets (stake)
• Average and biggest bet stake, return and profit
• Average and biggest profit per bet, day, week, month or year
• ROI, Yield
• Balances at each bookmakers and wallets
• Number of bets, stake, return and profit per bookmaker
• Bonuses, fees, adjustments, transfers, per bookmaker
• Number of open bets and stakes per bookmaker
• Log of transactions and bets
• Graphs
• Profit analysis by sport and market
• Many more

In our previous article – Record keeping – Best practices to keep track of your bets (part 1) – we talked about the importance of keeping records to get valuable information about your betting activity. Every successful bettor should keep track of his bets. We had also started designing an excel spreadsheet to do this task, and decided to record the following information:

• Bet types
• Transaction type
• Currencies
• Bookmakers
• Sports
• Markets
• Countries
• Bets
• Transactions

Let’s complete our sure bet tracker design.

Bet types

Bet types represent the type of each bet. We should use a bet type attribute if we want to classify our bets. We could, for instance, define types like “single bet”, “parlay bet”, “surebet”, “value bet”, etc. The Bet type entity should have a code, a name and an optional description.

Transaction types

Transaction types represent the type of each transaction. We should use transactions to record money transactions (besides bets) and transaction types will allow to classify and analyse transactions. These types represent investments, withdrawals, transfers, bonuses, fees and anything you’d like to consider. As bet types, you should keep a code, a name and an optional description.

Currencies

The Currencies entity will hold all the currencies we use (on wallets, bank accounts or bookmakers). Besides the currency code, name and description, we will need the current exchange rate. Each time we enter a bet or transaction, the exchange rate should be taken from here. In order to calculate global indicators, we should decide which currency will be our main currency. This one should have an exchange rate equal to 1, and all other currencies should include the exchange rate according to the main currency.

Bookmakers

Bookmakers are one of our main entities. Bookmakers’ information could include:

• Name
• Web address
• Username
• Password (it’s not a good idea to write down passwords, but maybe a password hint)
• Currency (the code that links to the currency entity)
• Notes

Please note we do not include a “current balance” attribute because we will have it automatically calculated from bets and transactions.

We could also use this entity to keep other accounts (ewallets, bank accounts). This will make it easier to enter transactions and calculate our overall balance. If we keep ewallets here, the Bookmakers entity could have an attribute to tell the type of account – such as B for Books and W for Wallets and bank accounts.

Sports

Sports are useful to analyse our profit with more detail. As most of the entities we are defining, you should have a sport code, a name and an optional description. We should have the sports we use most (football, baseball, hockey, tennis, american football and other). We could also have a record called “other sports” to use when we place a bet in a sport we don’t need to track.

Markets

As Sports, markets are also useful to analyse our profit with more detail. We should have the markets we use most (1X2, HA, AH, OU, etc.). We could also have a record called “other markets” to use when we place a real rare bet in a market we don’t need to track.

Countries

We could use this entity to identify the country where the event took place. For the sake of simplicity, we could also keep continents or even “World” in this entity, to enable continental or international competitions. For example, a bet in a World Cup match should include the “World” country, and a bet on the Champions League should include “Europe” country.

Transactions

All the previous entities (bet types, transaction types, currencies, bookmakers, sports, markets and countries) are not transactional records. We call them master records. Once we have recorded this information, it does not change a lot. Of course, as we keep betting we will need to add countries, sports, bookmakers. We can also change information (any field except codes), for instance, we would like to update exchange rates, or add notes to bookmakers. We can even decide to add new bet types or transaction types.

We will use transactions to increase or decrease balance or to move money between accounts. Transactions need to include:

• Transaction number
• Transaction type (the code that links to the transaction types entity)
• Date
• From (the code that represents an account – bookmaker or wallet)
• To (the code that represents an account – bookmaker or wallet)
• Amount

Transfers need two accounts. That’s why we included from and to. Other transactions only need one account. We should use “from” (because money leaves from the account) if money decreases (i.e. a fee, a withdrawal) and use “to” (because money arrives to the account) if money increases (i.e. a bonus, an investment). Experience shows that most transactions will be transfers between wallets and bookmakers (when you deposit into a bookmaker from your ewallet or when you withdraw from your bookmaker to your ewallet, these are in fact transfers).

We did not include the currency because currencies are part of the account. If you deposit on your Pinnacle account, the currency will be the one indicated in the Pinnacle record (bookmakers entity). In case you are transferring money, the amount is expressed in the “from” account currency. However, we could also add more columns to make this clearer. We could have two amounts (from and two) that would be expressed in each account’s currency, and we could also have two more columns to express these amounts in the main currency.

Bets

Finally!

Bets can include lots of information. We could start with these fields:

• Bet number
• Bet type (the code that links to the bet types entity)
• Date (and time)
• Event
• Event date (and time)
• Book (the code that links to the bookmakers entity)
• Stake (expressed on the bookmaker currency)
• Odds
• Return (expressed on the bookmaker currency)
• Sport (the code that links to the sports entity)
• Country (the code that links to the countries entity)
• Market (the code that links to the markets  entity)
• Outcome (a description of what you bet, i.e. over, under, home, away, etc.)
• Spread (to use in handicap or totals markets, to represent the handicap or total value)
• Notes

Notes:

This is our main entity and this is just basic information. If we want to keep surebets, we need to add more data, such as a surebet field where we will enter a number; all bets with the same surebet number should form part of the same surebet. If we want to keep details about parlays, this structure is not the best; parlays have many bet lines, with different sports, markets and odds, but only one stake. We think it is not necessary to make this design too much complex to have this information, but that depends on how important are parlays on your betting activity. If you want to keep details of your parlays, you need to represent bets as two entities (bets and betlines; the date, bookmaker, stake and return are part of the bet and the odds, sport, market, etc. are part of the betlines).

As with transactions, amounts are expressed on the bookmaker’s currency. We might want to include the amounts expressed on the main currency, so we would need to add another stake and result columns.

Depending on you specific needs, you may want to include other relevant information, as periods (e.g. 1^st half, 2^nd set, full time) or moment of bet (prematch, in-play). You could also use a list of predefined outcomes (instead of free text). All this requires more fields on each bet, and more entities (periods, outcomes and moments). It can turn your excel too complex and here is when you might start thinking of an application.

Arbitrage opportunities considering two way markets are easy to understand and to detect. For experienced arbers, just a fleeting glimpse at the following odds is enough to detect these arbitrage opportunities.

Almost all arbers will recognise these situations as arbitrage opportunities. How do we do it?

 

American odds.

Well, it’s quite easy to detect two way arbitrage opportunities on American odds; Positive odd must be higher than negative odds (considering its absolute value). Why is that?

Positive odds represent the profit for a 100 stake. +120 means our profit is 120 for a 100 stake.

Negative odds represent the stake necessary to win 100. -110 means we must bet 110 to win 100.

If the stake necessary to win 100 is less than the profit for a 100 stake on the opposite outcome, we have a surebet.

Decimal odds.

The situation is not so obvious on Decimal odds, but still easy. We know an odd 2 requires at least another 2, an odd 3 requires at least 1.5, an odd 4 requires at least 1.333, an odd 5, requires 1.25, an odd 6 requires 1.2, etc. We know it by experience, but the formula to detect an arbitrage opportunity is easy. You simply must add the reciprocal of both odds (multiplicative inverse: 1/odd). If the sum is less than 1, there is an arb.

Equation to detect arbs

Let’s prove it. Assuming a two way market with odds O1 and O2 for both outcomes, we want to know if these odds represent an arbitrage opportunity and how much to bet (both stakes, S1 and S2). The equations we want are:

Equation 1 – Return for bet 1 is greater than the sum of stakes, so that we have a profit.

Equation 2 – Both bets will have the same return, just to assume a balanced profit on both outcomes.

Equation 3 – Isolating S1 from equation 2

Equation 4 – Replacing S1 (from Equation 3) on Equation 1

Equation 5 – From equation 4

Equation 6 – Multiplying each side by O1 on equation 5

Equation 7 – Dividing each side by S2 on equation 6

Equation 8 –From equation 7

Equation 9 –From equation 8