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Lazy Sports Betting Tactics
How to beat the bookies in the over-under markets
How to convert between decimal and American odds
How to get an edge in betting
How to test the credibility of a tipster`s record
Kelly criterion method
How to use Kelly Criterion for betting
How Weather Affects Sports Betting
Increase Your Chances of Winning Long Term Betting on Sports
Intermediate and Advanced Sports Betting
Common sportsbetting myths
Advices on Betting Fundamentals
Betting do's and don'ts
Choosing a staking method based on your betting profile
Betting staking plans
Value betting explained
Sports-betting- a game of numbers
Market movement in betting
Types of odds explained
European types of bets explained
American types of bets explained
Martingale Considerations in Sports Betting
In-play betting
Accumulator betting
Mobile betting
A Crash Course in Horse Racing
A Crash Course In Sports Betting
American odds versus decimal odds
Bankroll management
Money management in sportsbetting- odds, edge and variance
Basic bet types explained
Paying for Picks
Betting on winning streaks
Betting psychology- a crash course about aspiring professional bettors
Popular Sports Betting Beliefs
Do you make these 9 sportsbetting mistakes?
Does intuition have a place in sportsbetting?
Exchange betting
Randomness in sportsbetting
Fractional versus decimal odds
Home team advantage analised
How bad at sportsbetting are you?
Reasons to Keep Betting Records
How bookmakers make money
How bookmakers work
How do betting exchanges work
Should You Bet on Multiple Sports or Specialize?
How do free bets work
How does luck influence short term betting
How good are betting tipsters
Sports Betting for Beginners
How loss aversion impacts performance
How many sports to bet on
How Much Should You Bet On a Sporting Event?
Staking-one method to improve your betting
How much you should risk per bet?
How Sports Betting Has Changed Over the Last 20 Years
How To Avoid A Big Sports Betting Loss
The art of multiple betting
The history of lotteries
The value of information in soccer betting
Three careers ideally suited to betting
Tips for Better Sports Betting Results
Types of Online Sports Betting Bonuses
Understanding and managing your risk of ruin
Understanding Horse Racing Bet Types
Understanding Live Betting
Value betting is an essential skill for bettors
Ways to Increase the Percentage of Sports Bets You Win
What are drawdowns and how to manage them
What are the most common mistakes the bettors make
What are the real chances of winning the lottery?
What distinguishes winning from losing betors
What is a handicap soccer betting?
What is the Fibonacci betting system?
What is the Labouchere betting system
What is the Martingale staking system
Why do we gamble? Irrationality and overconfidence
Why patience is an essential trait for any serious bettor
Poisson Distribution: Predict the score in soccer betting
Fixed Staking vs. Variable Staking
Basketball betting: Bet types explained
7 Sure-Fire Baseball Betting Strategies
How Does In-Play Betting Work?
To Parlay, or Not to Parlay?
Wisdom of the Crowds applied to betting
CASINO ARTICLES
A Novice’s Tutorial on Casino Gambling Games
How to Gamble with Dice – Popular Dice Games and Their Variations
How Online Casinos Helped Me Love Roulette Even More
My Top Three Tips for Getting Comps in Casinos
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5 Gambling Tricks You Can Only Use Online
5 LITTLE-KNOWN FACTS THAT AFFECT YOUR AVERAGE HOURLY LOSS IN A CASINO
5 REASONS CASINO GAMES ARE SO ENTERTAINING
5 Things All Casino Gambling Fans Are Sick of Hearing
5 Tips to Managing Your Casino Bankroll Effectively
The Five Most Important Tips I Ever Learned on Bankroll Management
5 Rookie Mistakes in Blackjack and How to Avoid Them
7 roulette variations probably you have never heard of
7 THINGS YOU NEVER KNEW ABOUT CASINOS
7 Ways Casino Players Sabotage Their Chances of Success
How to Tell If You’re About to Make a Mistake with Your Next Casino Bet
The 12 Types of People I Meet in Casinos – Analyzing My Fellow Gamblers
10 SURE-FIRE CASINO GAMBLING STRATEGIES THAT WORK
What I Love Most About My Three Favorite Video Poker Games
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Combining the Martingale System with Odds Bets in Craps
Which Bets on Which Casino Games Offer the Best Odds of Doubling Your Money?
What’s Next for Online Gambling?
Using Self-Discipline in the Casino
20 ONLINE GAMBLING TIPS
Going All-In – When to Bet It All in Poker
10 Things I Wish I’d Known About Roulette Before I Started
Who’s the Best Video Poker Player in the World
Are No-Deposit Bonuses at Online Casinos a Waste of Your Time or Worth Going For?
Are Online Casino Bonuses Worth Taking?
BEATING BACCARAT – WINNING SYSTEMS & STRATEGIES
CHOOSING THE RIGHT SLOT MACHINE
EUROPEAN VS. AMERICAN ROULETTE
EVEN MONEY CASINO BETS
Feel Confident When Gambling Online – 8 Tips to Help You Choose a Secure Site
Finding the Best Slots Online
Gambling and Poker Playing: 10 Things to Know
GAMBLING GAMES THAT ARE REALLY WORTH TRYING
HOW TO AVOID GOING BROKE AT THE ROULETTE WHEEL
HOW TO GET YOUR FIRST ONLINE CASINO SIGNUP BONUS
How to make a million playing video poker
How to Spend Your Gambling Winnings
HOW TO SURVIVE A BLIZZARD AT THE CRAPS TABLE
HOW TO WIN AT ROULETTE
How to Win Consistently at Casino Gambling
How to Win Consistently at Craps
How to Win Consistently at Roulette
HOW VOLATILITY WORKS IN CASINO GAMBLING
Is It Possible to Play Roulette as a Career (Or Even as a Part Time Gig)?
Is One Blackjack Game Better Than Another?
MONEY MANAGEMENT STRATEGY FOR YOUR NEXT CASINO TRIP
ONLINE CASINO DISPUTES
SKILL BASED CASINO GAMES: PROS AND CONS
The 5 secret joys of casino gambling
The Benefits of an Online Gambling Environment
The Best Long-Term Strategies for Playing Progressive Jackpot Slots
THE BIGGEST JACKPOTS IN ONLINE GAMBLING
THE EASIEST WAY TO LEARN BLACKJACK STRATEGY
THE HOUSE EDGE
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The Surprising Secret to Winning at Casino Gambling
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WHY IS THE DON’T PASS BET BETTER THAN THE PASS BET IN CRAPS?
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How good are betting tipsters

Betting tipsters often promise high strike rates that will win you a fortune. Although the promise of big profits is alluring, how can you tell the difference between a profitable tipster and a salesman. Read on to find out the two factors you need to evaluate before you decide which expert picks to trust.

In a previous article, Mark Taylor explained how luck influences betting and whether profit is always a sign of skilful betting. Using a series of coin tosses as an example, Mark used a binomial calculator to calculate the probability of making a profit after ten consecutive wagers.

The binomial distribution is well suited to 50-50 propositions like point spread or Asian handicap markets, where the odds for each side are close to even money, or a little shorter after the bookmaker applies his betting margin. Often, however, bettors bet on all sorts of different prices with all sorts of different stakes, for example 1X2 markets in soccer or match betting in tennis.

In such circumstances, we can rely on what is known as the t-distributionand the student’s t-test for statistical significance, which uses it. In this article, I explain how to use the t-distribution to gauge the performance of a betting tipster.

The length of a tipster’s record

The t-distribution is very similar to the bell-shaped normal distribution and for numbers of wagers above about 30, is to all intents and purposes the same thing. The t-test investigates the likelihood that a profit from a series of wagers could have happened by chance.

A return of 120% from 100 wagers at odds of 10.00 or longer is most likely to be a consequence of luck. Same returns from betting odds-on prices is an indication of skill.

The smaller the likelihood, the more probable it is that something else, like the bettor’s skill, is explaining their profitability. The t-test simply compares the bettor’s observed return to a theoretical expectation (assuming chance only) defined by the market they’re betting in. 

Usually this would be a loss equivalent to the bookmaker’s margin, or break even if the bettor is taking the trouble to find best prices using an odds comparison tool. The resulting t-score is then analysed to determine whether the difference is statistically significant.

It should be intuitively obvious that the larger the profitability the bigger the t-score and more statistically significant the betting history, in other words, the more likely it is that skill has played a part. The t-score is directly proportional to a bettor’s excess average return over expectation.

Similarly, the longer the history (for an equivalent return) the more likely it is that something other than chance is at work. Consider, for example, two bettors with a 120% return on investment. The first achieved it from 10 wagers, the second from a 1,000. Who is more likely to be the skilled bettor? 

If in doubt, think of tossing coins again. Landing six plus heads out of 10 tosses is obviously far more likely than landing 600 plus from 1,000 assuming only chance. Were one to land 600 or more heads, one might reasonably suspect the coin to be biased.

Similarly, we are more likely to conclude that a bettor with a long record of profitability is demonstrating skill. The t-score is in fact proportional to the square root of the number of wagers.

Long vs. short odds

Less intuitive is the influence of the betting odds. In fact, a 120% return on investment from betting odds around 1.25 will be a much better indicator of skill than an equivalent profitability from betting odds around 5.00. Betting on lower probability outcomes (longer odds) is inherently riskier (assuming equivalent stakes) because it is more at the mercy of random variability.

To put it another way, returns are more volatile. 19 or 21 winners at odds of 5.00 will give returns of 95% or 105% respectively. In contrast, 79 or 81 winners at odds of 1.25 will show 98.75% or 101.25% profit over turnover. Betting longer odds implies taking more risk to get more reward. 

We can see the influence of the betting odds by means of the standard deviation in profits and losses of the betting history. For level staking, the standard deviation can be approximated by the following expression.

To approximate standard deviation for level staking:

 

Where o represents the average odds for the betting history and r is the bettor’s actual return. The standard deviation in profits and losses betting at odds of 5.00 is more than four times larger than when betting at odds of 1.25. Assuming that expected returns (based on luck only) are 100% (or break even), the t-score is given by the following equation: 

 

Where n is the number of wagers. Consequently, the t-score for equivalent returns and length of betting history will be more than eight times smaller betting at odds of 5.00 compared to 1.25.

It should be clear that superior yields achieved through betting longer odds, as is typical in markets like horse racing, are not necessarily a sign of better forecasting talent. The same amount of luck will deliver much bigger percentage returns.

Hence, comparisons of betting histories that consider only percentage returns, as is common when ranking tipsters, are fundamentally misleading. By taking into consideration the betting odds, the t-score provides a measure of the quality of the risk-adjusted return in excess of expectation.

Calculating chance 

The final step is to convert the t-score into a probability (the p-value) that a history of profitability could arise by chance only. Those with Microsoft Excel can make use of the TDIST function. This takes the form TDIST (t, degrees of freedom, tails), where t is the t-score whilst degrees of freedom is the number of independent pieces of data and is equivalent to the number of wagers minus one.

The tails argument can be either one (for the one-tailed t-test) or two (for the 2-tailed t-test). Since we’re really only interested in whether a profit is statistically significant, the former is preferred in this case. Alternatively, one can make use of an online calculator where these values can be inputted.

The table below shows some examples of t-scores and their corresponding p-values for betting histories of 100 wagers and a return on investment of 120%.

Odds

t-score

p-value

1.5

3.33

0.06%

1.75

2.46

0.78%

2

2.04

2.19%

2.5

1.60

5.63%

3

1.36

8.83%

4

1.09

13.89%

5

0.94

17.56%

10

0.62

26.98%

25

0.37

35.45%

50

0.26

39.72%

Evidently, the average odds at which someone bets has a big influence on whether their profitability can be considered lucky or skilful. A return of 120% from 100 wagers at odd of 10.00 or longer should clearly be considered largely a consequence of luck.

By contrast, if a bettor was to show the same return betting odds-on prices, it is far more likely that the profitability has arisen because of their skill. Consequently, when comparing betting histories, for example from tipsters, it is not enough just to analyse their percentage returns, but also the length of their records and the odds at which they were achieved.