Roulette Software, Systems, & Simulations


Mind the Gap

Mind the Gap is a program for those who like betting individual numbers. It tracks the number of "gaps" for each number and updates their average length. A "gap" is defined as the number of no-hits between successive hits. So for instance (referring to the screenshot below) the current "gap list" for #21 is {26,3,21}, meaning that it first hit on the 26th spin, it then hit 3 spins later, and its current status is 21 spins without a hit. The average gap for #21 is therefore equal to ( 26 + 3 + 21 ) รท 3 = 16.7.  

            the Gap

The average gap for each number is updated every spin. In the long run, the average gap for every number approaches 37, but in the meantime it could vary significantly from this value. A number could not show up for 300 spins (in which case its average gap would be 300) or it could hit 2, 3, or more times within 37 spins. The art of playing roulette consists in trying to predict how long these gaps will be!

Important note : The gap lists shown are truncated at 8 gaps, so on the 9th gap the first gap will be removed from view. But this is only because of space limitations; the average gaps are actually calculated from whatever the gap list is (however long it is) even though only a maximum of 8 gaps are actually shown.


Enter the stream of spins by clicking on the corresponding numbers in the layout on the left. There are two ways you can select bets:

  1. Manual : To add a number manually, simply click on its gap list and it will be added to the layout.
  2. Auto : Bets can be placed automatically based on the average gap value. In the bet selection area, select the radio button according to whether you want numbers bet that are More Than / Less Than the gap value you enter into the edit field. When or if the gap value for numbers meets this criteria they will be added to the layout.
You can of course mix and match the way you select; any combination of manual and auto. Whenever a number is selected (either manually or automatically), those numbers will be highlighted in cyan on the layout and the number of #s being bet will be updated. This number is located to the left of the zero. The spin count is displayed in dark blue to the right of the zero.

The bank will be updated automatically every spin. To vary the stakes (chips per #), click the +/- buttons to the right of the bankroll value. If you need to clear the layout (remove bets), click the Clear button. The Reset button resets the gap and average gap lists, and resets the spin count (located to the right of the zero in the layout) back to 0. This is a useful feature if you want to bet after a certain number of spins or when gap lists reach a certain length, for example.

Check out the video demo to see the software in action.

Buy now for only $9.95. Immediate download.

After downloading, unzip the file and extract the contents to a folder of your choice. To run the program double-click the executable file mindthegap.exe.


This software may be useful for all who like to create and test systems, or it could be used as a standalone spin generator (either RNG or recorded spins on a file).

Of course every system creator hopes that their system is going to make a profit, but if it does, are the results "statistically significant"? Basically, what it means for a result to be statistically significant is that it is unlikely to have occurred by chance. In other words, there is something more going on than mere randomness. You could argue that it doesn't matter whether the result is significant in this sense because the bottom line is : does the system make a profit?

Sure, but it's easy to be misled into thinking that the system has real merit if it makes a profit in the short term, when in reality you've just been lucky. This is especially so if you're using some kind of progression which recovers losses. If using a progression, a system could do rather well (profit-wise) in circumstances where flat-betting would have returned an overall loss. The benchmark of a "good" system is that it returns a profit flat-betting over time, and in order to achieve this you need an "edge"; ie the system's results (in terms of bet selection) will be statistically significant. The program tells you whether this is the case or not.


Basic Usage

There are three ways to enter spins.

  1. Click on the numbers in the layout on the left. This would be the preferred way if you're getting the spins from an online casino in real time.
  2. In the "spin options" area on the right you have the option of selecting RNG or spins from a file. To use RNG select the RNG radio button and then click the "Get A Spin" button to get a spin. Note that clicking this won't automatically add the spin to the marquee (you will have to additionally click the relevant number in the layout to do that).
  3. To get numbers one at a time from a spin file, select the "Spin File" radio button in the spin options area and then click the "Open File" button. When the file has been loaded one spin at a time will be displayed when you click the "Get A Spin" button. As with the RNG option, you will need to click the corresponding number in the layout to add the number to the marquee. The spin file should have one number per line (if it's not in the correct format you may get a warning that the file is corrupted).
Actually, you don't need to enter spins at all in order to measure the statistical significance, you only need the quantity of numbers bet on and whether the result was a win or a loss.

When you have the result of a bet, ensure you have set how many numbers were bet by clicking the combo-box at the top right and selecting the number of numbers (between 1 and 35). On starting up the program the label "NTB" (Numbers To Bet) is shown in the combo-box. Then click the "W" (win) or "L" (loss) button depending on the outcome. The significance level will be updated on the first win and every bet thereafter. The initial bankroll is zero and assumes that one unit is staked on each of the numbers selected.

Saving Results

When you close the program you will have the opportunity to save the results. This file can be reopened when you start a new session by clicking the "Results File" button. The final results from the previous session will be loaded and you can continue as though the session was uninterrupted. So you could have multiple systems being tested at any one time, with a separate results file for each. The results file consists of two columns of data : the wins/losses and the sequence of significance probabilities. You could import it into a spreadsheet to see (for example) if there is any trend in the significance, or to do some other analysis.

Note that you can only save results when closing the program, so if you want to start testing a new system halfway through a session and want to save the current results you will need to close the software and restart it. If you want to start a new session but don't need to save the results, just click the "Clear" button to reset everything.

The meaning of "Significance"

The significance level is a probability; it is the probability that you would have got the results you actually have (ie, the number of wins versus losses) given that the system had no merit at all. In other words, the assumption is that the bet selection is no better than betting randomly. If you think about it, you'll realize that a low probability is more significant than a high one under these circumstances, because it is evidence that the result is not just due to chance. Conventionally, the threshold below which the result is deemed significant is 5%, meaning that the probability is 1 in 20 that the result would have occurred by chance. If the trend of the significance level is towards zero over time it indicates a genuine edge. Significance levels less than 0.05 are shown in green, otherwise they are shown in red.

A word about "sample size" and the interpretation of significance. The more bets you make which continue to show significant results, the less likely it is that randomness is playing a part. This doesn't mean you have to make thousands of bets, but on the other hand, you might be betting just 1 number which happens to hit twice in the first 10 spins, and obviously this doesn't mean you have winning system! Generally speaking, if you're playing few numbers you will need more data than if you're playing many. If in doubt, get more data.