Clash of Clans Troop Efficiency

For the past couple months, I’ve been filling my downtime by playing Clash of Clans, a MMO base builder game where you can plunder other player’s bases. In hopes of improving my attack strategy, I’ve read several guides on how to conduct the best attacks in the game. One thing that’s missing from these guides, though, is an analysis of how efficient the attacks are. It’s one thing to completely annihilate your opponent, but it’s another challenge altogether to annihilate your opponent while expending as few resources as possible.

To start up the conversation on attack efficiency in Clash of Clans, I’ve created several visualizations below looking at the cost and housing efficiency of every troop in the game. All of the data in these visualizations comes from here, and I’ve provided a tabulated version of the data here. You can access the interactive versions by clicking on the image.

Troop cost efficiency

Unless you’re extremely patient, you’re probably going to be raiding other player’s bases to steal their resources so you can build up your own base. That means that you’ll want to do as much damage to your opponent’s base while spending as few resources as possible. Below, I’ve plotted the DPS and HP that every troop provides for every Elixir it costs. Each point represents an upgrade level for the troop. I had to plot the Elixir and Dark Elixir troops separately because there isn’t a clear conversion rate between Elixir and Dark Elixir.

coc-troop-cost-efficiency-elixir

(note that the axes in the chart above are on logarithmic scale to help display the data better)

For experienced players, the main result here is likely unsurprising: Barbarians, Archers, and Goblins give you the biggest bang for your buck. Don’t go raiding for resources with Giants, Wizards, or (worst) Dragons or you’ll quickly find yourself losing resources every time you go raiding.

coc-troop-cost-efficiency-dark-elixir

It’s hard to compare Elixir cost efficiency to Dark Elixir cost efficiency, but it’s fairly clear from the plot above that Minions are the most cost effective Dark Elixir troop in the game. Witches may seem abysmal on paper until you remember that their main role is summoning Skeletons to attack the enemy base.

What I found particularly interesting in the interactive versions of these plots is that almost every troop in the game becomes less cost efficient as you upgrade them. Upgraded troops may be stronger (and more fashionable), but you don’t get as much out of them per Elixir.

Troop housing space efficiency

Of course, Clash of Clans isn’t always about raiding villages for resources. Especially during Clan Wars, you’ll want to completely wipe out your opponent’s base so your clan gets more victory stars. In this case, your limiting resource becomes housing space. Every base can only support so many troops, and some troops take up more space than others. Below, I’ve plotted the DPS and HP that every troop provides for every housing space it takes up.

coc-troop-housing-efficiency

The Golem stands tall as the ultimate tank in the game, whereas Wizards dish out the most damage per housing space (with Goblins as an underrated runner up). Higher-level Barbarians and Balloons seem to provide the best of both worlds, providing both ample DPS and HP for every housing space they take up.

Again in the interactive version, you’ll note that — unsurprisingly — all troops provide more DPS and HP per housing space as they’re upgraded. This is ultimately the reason you should always upgrade your troops, even if they provide less bang for your purple buck.

You’ll also notice that some upgrades provide far more of an advantage than others. The level 5 Wizard upgrade improves the Wizard’s DPS per housing space from 32 to 43 (+34%), whereas the level 6 upgrade only improves it to 45 (+5%), which hardly seems worth the exorbitant level 6 upgrade cost. The Balloon’s level 5 and 6 upgrades take it from an underwhelming 14.4 DPS/HS & 56 HP/HS all the way up to 32.4 DPS/HS (+125%) & 109 HP/HS (+95%), marking them as two of the most cost effective upgrades in the game.

Caveats

There are of course some caveats to the results I outlined above. Particularly, if you followed the housing space efficiency chart, you may be inclined to spam Giants at your enemy and avoid Healers and expect to wipe out your opponent’s base. Or worse, if you followed the cost efficiency chart, you may be inclined to spam Goblins and completely avoid Wall Breakers for the most cost efficient attack.

Keep in mind that every troop has a particular purpose. Healers are useless by themselves, but they have great synergy with high-HP troops like the Giant. Goblins may have high DPS, but they attack defenses last and will die in droves if Wall Breakers don’t open up the base for them. Think of these charts as a stepping stone, not a Rosetta stone, for crafting your perfect Clash of Clans attack strategy.

Dr. Randy Olson is a Senior Data Scientist at the University of Pennsylvania, where he develops state-of-the-art machine learning algorithms with a focus on biomedical applications.

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  • Dave

    Two comments:
    1. Not taken into account is the effect of walls on troops, nor the preference of troops for particular building types. It sort of invalidates the results due to the fact that there are clear maxima in your data, but armies of JUST those troops will fail again and again. Defense mix and placement informs troop selection.
    2. I think that out of the data presented, the key metric here is space efficiency rather than cost, as elixir and DE are effectively inexhaustible resources, while every village has a fixed camp size. You really need to get the most out of those slots.

    • Not taken into account is the effect of walls on troops, nor the preference of troops for particular building types. It sort of invalidates the results due to the fact that there are clear maxima in your data, but armies of JUST those troops will fail again and again. Defense mix and placement informs troop selection.

      Yep! I mentioned this in the Caveats section. It’s tough to mathematically incorporate unit range and the effect of walls. I’m pretty sure we’ll need a simulator for an advanced analysis like that.

      I think that out of the data presented, the key metric here is space efficiency rather than cost, as elixir and DE are effectively inexhaustible resources, while every village has a fixed camp size. You really need to get the most out of those slots.

      As a TH7, I beg to differ about DE being effectively inexhaustible… 😉

  • I would love to see some data on strategies as well (that would incorporate multiple set of units) and their overall performance!

    • To measure performance, I’m pretty sure we’d need a simulator. I proposed collecting data on people’s attack performance over at /r/ClashOfClans as an alternative, but I haven’t found anyone willing to put in the effort to do the data collection.

      • Aaron

        You have another problem here. The strategy at which people drop troops will make it very difficult to compare. For instance, if they just drop all into the left corner, or spread them all around the edge, or actually think out what they put where.

        On top of that, the infinite variation of bases to be attacked doesn’t help. You would need to have a developer account, and attack the same base several (or hundreds of) times.

        Other than than, I enjoyed reading this! I’m in the process of creating an upgrade assistance for clash of Clans. Will be posting it on /r/ClashofClans soon for review and criticism. Keep an eye out for it, I’d like your opinion.

  • Rob

    What TH are you currently at? What is the mix of troops you do for BAG and BARCH raids?

    • I’m currently at TH7 trying to max that base out. I usually do 3:1 A:B barching raids and hide in the low trophy range. 😉

      One limitation of this analysis is that it doesn’t reflect the fact that Archers can attack from a range, when is a huge advantage when raiding. Especially when facing splash damage defenses.

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  • Clasher

    With the new update coming out it’s going to make using troops other than barbs, archers, and goblins even more of a waste because before if you did a lot of farming/raiding it really didn’t matter too much how much elixir your armies used because you always would have way more elixir than needed and never enough gold. Now that elixir will be used to upgrade walls it will be important to conserve elixir.

    • I’m really looking forward to this upcoming update! Sooo much Elixir sitting around…

    • Axalt

      I disagree about the relative scarcity of gold to elixir. I always feel I’m more short of elixir because I’m still in the process of upgrading troops. Plus, even bad raids are net positive gold, whereas you need to offset the elixir cost of your army.

      • Plus, even bad raids are net positive gold, whereas you need to offset the elixir cost of your army.

        You have to also consider the cost of searching for a good target, which can be quite expensive depending on how picky you are.

  • Ive been trying to find someone demonstrating a data-focused approach to this game. Love this! I’d really like to see a data analysis of the ideal base setup. What setup optimizes damage distribution?

  • alvi

    good stuff.. do an analysis of the defensive
    buildings next! haha

  • Hey Randy! Nice post I wrote something a while back that used linear programming to optimise a raiding party. I did that based on a very simple approximation of efficiency (liner combination of cost and attack). I might revisit that with your efficiency ratings!

    http://drvinceknight.blogspot.com.br/2014/05/wizards-giants-linear-programming-and.html

    • Nice work, and thank you for sharing that here! Did you post it to http://www.reddit.com/r/ClashOfClans yet?

      • Vince

        I didn’t but it found it’s way over there on it’s own (which was cool). That kind of pushed me to try out reddit and in turn find your post! 🙂

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  • Good post. Like others have said, it’s hard to rank strategies/compositions because of a multitude of factors. I shared the combination I’ve found to be most efficient on my blog. Cheers.

  • jeff reiter

    okay, from a strictly return per unit of cost perspective, it would appear that this analysis leads to the best conclusion from an efficiency point of view. it fails, however, to analyze from an effectiveness point of view. efficiency is not valuable unless its effective. wizards, for example, are viewed as less efficient due to their cost; however, if an attack fails to yield the desired result, what use is the investment? i have found at the town hall 9 level, that wizards, in combination with other troops, are invaluable in achieving results. i can wipe out a town hall 10 to 100 percent and get it all. some troops become invincible. a queen with a couple of healers never dies and completes the attack without requiring regeneration.

    as a second observation, it depends on your goal. in my current strategy, my goal is to get as much black juice as possible with the idea of upgrading all my black forces and then shifting my troop concentration to entirely black with the new goal of maximizing my pink juice yield. a black attack force yields 100 percent of its pink loot and uses no pink in the process. a pink force yields 100 percent black juice with no investment loss. gold is irrevelant as it is a constant loss based on the willingness of the player to search for targets. as with all human endeavors, quality is based entirely on fitness for use, an so to this principle applies to the fantasy world with the same vigor.

    • APenNameAndThatA

      The goal of the analysis was not to be all inclusive. Just because there are other things to consider does not make it all right for you to be a pompous twat and say, “it fail, however”. So

  • David Hunter

    Randy, great work. Mind if I link to this from my COC website?

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  • Great post. Nice to see the plots. Thank you for this.

  • Frank

    I’m not sure, are you calculating DPS versus upgrade elixir cost or versus training cost? The reason I ask is because the Wizard gets more efficient on a DPS per training elixir cost for each upgrade, not less efficient

    • It’s versus training cost. If you check out the interactive version, you’ll see that your expectations are corroborated: Wizards increase their DPS per training cost as they upgrade to higher levels.

      • Gavin Connew

        Just out of curiosity, did you ever manage to compile a chart outlining the best all round army combo for war attacks? Maybe a combo for each town hall level? I am considering restarting from the beginning and it would be handy to know a steadfast reusable army to stick to up to town hall 9.

        • Hi Gavin. I haven’t revisited this topic in a while because I decided to quit CoC. Darn game was too time consuming… 🙂

  • chris

    Nice, but one thing to keep in mind is that elixir becomes worth less than it was before you level up the collecters. Would like to see a graph of the real elixir cost instead of the nominal cost of elixir

  • definingsound

    A conversion between elixer and dark can be estimated by the total elixer storage available / total dark storage available, or normal elixer gains / normal dark gains.

    I don’t see the benefit to single-factor comparison plots, except to provide a visual representation of something that is rather easy to determine using mental estimates (i.e. 5 barbarians @ 23 dps is about 120 dps, but 1 giant taking the same housing is 31 dps – no graph needed there).

    Instead of comparing to either cost or housing, why not compare to both factors by dividing cost/housing. This will capture more of the relevant data in one plot, such as dps / (cost / housing), or hp / (cost / housing). This will convert all your data into a per-1-housing-used metric.

    • Rocco Stevens

      I’m not sure I agree with those methods of determining dark to regular elixir conversion rates. Comparing total storage? how is that relevant to the value? Comparing normal gains? Do you mean from farming? The dark drills are way more efficient than the regular collectors. Most resources are gained from raiding anyway so farming capability doesn’t determine normal gains. The capabilities to store and farm the resource do not reflect its value in regards to producing troops.

      Here is how I would determine a power exchange rate between dark and regular elixir: Create a troop power rating (PR) by multiplying DPS x HP. Find the PR to elixir cost ratio of all the regular troops and then take the average of that. Find the PR to dark elixir cost ratio of all the dark troops and then take the average of that. Compare the two average ratios and you can determine the power exchange rate between the two types of elixir… which would allow Randy to combine his two cost efficiency charts into one like with the housing efficiency chart.

      Now that I have explained HOW to do this maybe somebody actually will.

      • definingsound

        Rocco: Players are given 2 dark drills, and 6 elixer collectors. A maxed TH8 can collect 45 de/drill/hr, or 3.5k elixer/collector/hr. So from collectors only, we see 90 dark elixer per hour, and 21k elixer per hour. Not sure how you determined that de drills are “way more efficient” that elixer collectors. A maxed TH8 collects 233 times more elixer than dark elixer, over the same time period.

        Your Power Rating idea sounds interesting at first, but how can we include a healer (negative damage?) in the total? How can we include the witch’s skeletons? The wizard/dragon/valk area of effect damage? The wallbreaker’s preferences for walls? The ability to fly or jump over walls?

        I’ll do your math as a maxed th8, and I’ll ignore the wb’s and healers: power rating (dps * hp) divided by cost averages 14 for elixer troops, and 600 for dark elixer troops. So with your conversion idea, dark elixer is worth 43 times what elixer is worth. Your math turns out to be almost the same as an estimate based on the ratio of total storage available.

        For my style of play, I consider dark elixer to be worth about 100 times the value of elixer. Everyone should have a different value, based on their preferred troops/style of play.

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  • Rocco Stevens

    Excellent post. Very interesting analysis and thank you for sharing the tabulated data as well. I was looking all over the web for a basic troop stat spreadsheet and so far your .csv file is the best I have found. I am going to add data for attack range, movement speed, training time, upgrade costs and upgrade time. Also I will add a couple extra columns for special considerations like preferred targets, etc..
    Once I get it all together and create some visualizations I will post here. Thanks again.

    • Thanks Rocco. Make sure to double-check the values in my csv file. I haven’t followed Clash of Clans since I made this post, so I’m not 100% sure if any of these values have changed since I published the data.

      • Rocco Stevens

        I do think it needs a few updates… but still the most comprehensive simple spreadsheet that I’ve found yet

  • Bryan Luikart

    So funny a Jason Moore post-doc. Thanks for the charts. -Dr Luikart.

    • Gotta dabble a little bit everywhere. 🙂

  • Horacio Moran

    It is nice to see an analysis at a doctor level. I’ve already thought about this approach to the game, and we should consider that powerful unit, let’s say a pekka, that has a great hit point level will be dealing full damage that is supposed to do until it is completely destroyed. Besides, if you took a group of barbarians, in a total cost equal to a pekka, they would be dealing less and less damage until the last one is destroyed.

  • rusher

    hi randy that is the good work i have always been telling guys who use giant healer combo to take lots of goblins with them they dont believe it! but if u use giant healer with no goblins u will most likely run out of time goblins deal DOUBLE the stated dps against resources they are really underestimated. i have had an idea to train some sort of reinforcement learner to optimise the troops but this will require a lot of trial and error which is expensive since there is no coc simulator,, anyway i work out the dps for troops and hp per housing it turns out that giant healer followed by goblins is quite efficient costing 40K approx to train while starring a lot of bases with 200K+ of resources. another idea would be to have players make a database of their troops in attacks and the result they got given the buildings in the defending village including resource, defensive and other buildings then use that large data to train a learning algorithm

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    This is the best article i have ever seen about clash of clans. For sure!

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