So we appear to be in a rut of unbalanced war matches lately and no one likes ruts. Basically this is because there are not many clans similar to ours (number of th10, th9, th8 & th7). CofC tries to match us with an equal clan, but because there are so few other clans that are our equal we are being randomly matched with clans that are significantly stronger or weaker. In contrast, the composition of th10, th9, th8 & th7 that we had around one month ago was very common and we were finding very balanced matches and thus winning because we are awesome.

The below diagram illustrates this theory. The left square is our current range of matches. The colored circles are opponents. The game randomly picks a match from our range of opponents. The right square is our old composition.

It is an algorithm which takes the geometric mean (assigning low weight to outliers) of the sum of our members' average building/troop/spell levels. This gives us a number and we are paired with a random clan from a range of other clans NEARBY (rarely equal to) that number.

"



Tonight we had a very long search for war and finally found a pretty wonky match (40 th10 vs our 13 th10). I have made another graph to explain how matchmaking works using an iterative algorithm (again, in theory). On the left is the time it takes to search for a match. On the bottom is relative clan strengths (cumulative building/troop/spell levels) with us at a middle strength of five. Every few minutes of the search where no opponents are found in a nearby strength range, the range expands and the search starts again. Eventually after 30 minutes of iterations we are searching a huge range of clan strengths and matched with the first possible opponent, who is most likely to be far too strong or far too weak since they were found in the last iteration.

One simple way to abuse this algorithm is to cancel the search after 5-10 minutes and just try again later."



Finished a plot that illustrates why we are encountering too weak or too strong matches recently. Note the recent dramatic increase in number of th10 and decrease in number of th7. This makes us very unbalanced and the matching algorithm for wars may only work well for ideally balanced clans.

The flat green line represents the trend of our composition a few weeks ago during a solid win streak. The high slope red line represents our current composition."



After several matches using my suggestion, we have only seen balanced matches. Went from consistent totally unbalanced matches (40 th10 vs 13 th10) to consistent matches with almost identical clans. All the "solutions" for future updates are amusing, but this is the only functional method of finding a good match if you are having balance problems.

Dozens of matches later, using this method we have not experienced a single mismatch.







Start search, wait ~10 minutes, cancel and restart. This prevents the matching algorithm for searching for clans far out of your range.





Attaching a relevant quote.



Originally Posted by xTrain Originally Posted by Great thread and insight...



In regards to this, does anybody know what a "common" clan looks like in order for a quick and easy match up? Our clan is a size of 10 right now, eventually heading to 15. My main concern is that our top guy is level 140, close to a maxed out TH10. We have 4 strong TH9's that are all close to max, and the rest are strong TH8 and 1 TH7.



What kind of TH levels should we be adding to our mix to avoid a serious mismatch?



Developers have stated that clans trying to recruit a few very low level players into their clan to reduce their opponent levels are "shooting themselves in the foot." This implies two things, first they are likely referring to a geometric mean code line in matchmaking (extreme outliers hold little weight) second that therefore your one very strong player weighs little as well. In my opinion this is an extreme advantage to your clan in war.



In order to explain what kind of TH levels you should look for, I would like to break down the geometric mean coding that I suspect SC is using in matchmaking. I will assign an abstract value to "player strength" where a developed th9 is stronger than a midrange th9 which is stronger than a fresh th9.



Player Strength TH Level 10 Developed TH10 9 Midrange TH10 8 Fresh TH10 7 Developed TH9 6 Midrange TH9 5 Fresh TH9 4 Developed TH8 3 Midrange TH8 2 Fresh TH8 1 TH7

Analysis- You said 1 Developed th10, 4 developed th9, 4 midrange th8, 1 th7. Mathematically this reads: geometric mean = (10*7*7*7*7*3*3*3*3*1)^(1/10)=4.3 ( Slightly above Developed TH8)



I interpret this to mean that when your war match is calculated you are searching for a clan whom are also slightly above developed th8 when averaged (this could be a clan with a wide spread of th levels like yours, or a clan of 10 fresh th9 or maxxed th8). Recruiting strong th8 and 7 will thus bring your strength down, resulting in matches with more common (low level) clans and vice versa.



Note- The matching code uses (probably) an iterative algorithm along with geometric mean. If the search runs longer than 5-10 minutes you will likely be paired with a significantly stronger or weaker clan. This is explained in the OP. To prevent this, restart the search after 5-10 minutes .



Note2- Hearty congratulations if you read and understood any of this. For your purposes common refers to low level.Developers have stated that clans trying to recruit a few very low level players into their clan to reduce their opponent levels are "shooting themselves in the foot." This implies two things, first they are likely referring to a geometric mean code line in matchmaking (extreme outliers hold little weight) second that. In my opinion this is an extreme advantage to your clan in war.In order to explain what kind of TH levels you should look for, I would like to break down the geometric mean coding that I suspect SC is using in matchmaking. I will assign an abstract value to "player strength" where a developed th9 is stronger than a midrange th9 which is stronger than a fresh th9.You said 1 Developed th10, 4 developed th9, 4 midrange th8, 1 th7. Mathematically this reads: geometric mean = (10*7*7*7*7*3*3*3*3*1)^(1/10)=4.3 ( Slightly above Developed TH8)I interpret this to mean that when your war match is calculated you are searching for a clan whom are also slightly above developed th8 when averaged (this could be a clan with a wide spread of th levels like yours, or a clan of 10 fresh th9 or maxxed th8). Recruiting strong th8 and 7 will thus bring your strength down, resulting in matches with more common (low level) clans and vice versa.- The matching code uses (probably) an iterative algorithm along with geometric mean. If the search runs longer than 5-10 minutes you will likely be paired with a significantly stronger or weaker clan. This is explained in the OP. To prevent this,Hearty congratulations if you read and understood any of this.







Update: Several clans have reported very unbalanced matches from very short search times, this is why.







Originally Posted by Greentangent Originally Posted by Clans are matched based on STRENGTH. This is calculated using a geometric mean of the sum of members structure/troop/spell levels. A geometric mean is different from a numeric mean in that extreme outliers (very strong or very weak) numbers weigh less/little. Refer to the geometric mean solution on page 7 of this thread with these figures for proof.



If your clan has 35% very strong members (e.g. th10) and 65% very weak members (th4) or vice versa, your clan strength is somewhere in between and you will likely be matched with a well balanced clan near that strength, but this could vary widely as there is no clear middle strength. In the posters' case, I surmise that he has some very strong players and very weak players. This could lead to a match with a clan of 100% moderately strong players.



Examples of well balanced clan levels: 120, 115, 110, 105, 100, 95, 90, 85, 80, 75

Or: 100, 100, 100, 100, 100, 100, 100, 100, 100, 100



Example of poorly balanced clan levels: 120, 115, 110, 105, 50, 45, 40, 35, 30, 25

Update:

Originally Posted by SuperSteve{SuperCell} Originally Posted by Also keep in mind that clan matchmaking is based on clan composition, and not average strength of the entire clan. As such, adding lower level member to your clan will not help you find easier matches, and will backfire in the form of providing more 3 star wins for the opposing clan against the low level members.



Originally Posted by Greentangent Originally Posted by It really seems like CW is going to pot lately.



Obviously clans are matched on strength and therefore I can say that there are multiple ranges of clan strengths. I see patterns emerging in various ranges. Some range of strengths will be full of clans that have no clue what to do (lower level clans). The real problem is the upper strength ranges (eg at least 15 th10 in clan). I have found that likely most of the clans in this range are shameless TOS violating fluffybunnies and rule-abiding clans will forfeit against these players. See IIB and ITD war logs in this forum, they never have a good war that requires any skill, all of their opponents immediately forfeit.



I am experimenting with different clan compositions to avoid these ranges in pursuit of good wars, supposedly what SC intended....



Convo with leaders-

" That corresponds to 7-8pm Beijing time. Very odd that they are not finding asian clans during asian primetime. I think our current method of starting at 4am Beijing time will work to avoid them.



It's utterly disheartening that fluffybunnies are becoming prolific and you are correct that even if we are the best players in the world we are no match for fluffybunnyers. The only thing that we can do is avoid them; fortunately I think we will be able to do that by using very specific th composition. Many think that it is counter-intuitive how I reject th9/10 and recruit th7/8 but this is how we will avoid fluffybunnies.



I totally agree that the realm of top war clans are likely nothing but fluffybunnies, but fluffybunnying takes a lot of effort and low levels are much less likely to be this invested. If we can maintain half of our clan as skilled low levels then we will be matched with similar clans who are also less likely to be fluffybunnying. Sadly we are basically barred from becoming a full th10 trophy clan if we want to war fairly. If we do encounter a clan like this ill no longer support humoring them; we will use all gobs in war cc, gob attacks etc.



Metadata is the game; we will make some strange compromises and continue moving forward."

Originally Posted by Greentangent Originally Posted by I have not speculated on other aspects of the algorithm because I lack enough evidence, however I suspect that another line of mathematical code may try to match number of thX to number of thX. See example in OP of "well balanced clan levels" e.g. a clan with a range of th10-th8 will not be matched with a clan of exclusive th9 even if they have similar average strengths. Or perhaps the algorithm does something like match quarters e.g. algorithm looks for one clan with similar strength of your top 25%, similar strength in second, third and fourth quarters uniquely.



Bear in mind that "composition" is a description and not a mathematical value, which is what SC uses to find a match. Aside from developers' access to code, all we have is theory about what this could be. Some theories are pretty good though (gravity).

Originally Posted by Greentangent Originally Posted by 2. Amazingly I think this may be correct; after 2-3 hours on the short cycle recently we have decided to try 20 minute search times and have in fact found good matches in both low and high level clans. It is likely that there would be no announcement for this sort of change other than already having said "we are constantly working to improve matchmaking" so this can happen quietly at any time. It would be reasonable for SC to put a minimum time on the search to prevent what I once called "abuse or short cycle" and expand the time iteration. This would both improve balance in matchmaking and prevent/alleviate the need to reset after 5 minutes to find a balanced match.



Another search after my quote has resulted in a 15 minute match that is fairly balanced (+-4 th10, th9) which is well within what I would consider tolerable and balanced, however a few weeks ago when 5 minute resets were working normally we would almost always have matches with identical number of th10, th9.



The fact that even a few observing that something has changed with matchmaking indicates a very real possibility that the algorithm has been improved.