Play Smarter, Not Harder --- An Analysis of My 20 Most Recent Dota2 Games

The Objective

In a match of Dota2, two teams, the Radient team and the Dire team, each of 5 players, play against each other with the goal of destroying the opponent team’s ancient.

Figure 1: Ancients. The left one is the Radient ancient and the right one is the Dire ancient.

At the beginning of the match, the drafting stage, all players take turns to select their heores with unique abilities. As an example, my favorite hero, ember spirit, is shown in the figure below. The icons in the lower right corner represent the unique abilities of ember spirit. After the drafting is finished, the match begins and the two teams start to work their way to the opponent team’s ancient.

Figure 2: Ember spirit, an example of 1 of the 119 heroes in Dota2.

Figure 3: An example of how a hero look like in game. The hero presented here is ember spirit.

But How?

Before one team can reach another team’s ancient, they must at least destory all the towers, which is shown in the figure below, (Marked as T1, T2, T3, T4 on the map) in one of the three lanes, the top lane, the mid lane, and the bottom lane. In most situations, each team will allocate 2 players in the top lane, 1 player in the mid lane, and 2 players in the bottom lane. In order to destroy the towers, the players need to grow stronger than the opponent players that are defending the towers. Players grow stronger by farming gold to purchase items, and gaining experience to strengthen their abilities. Gold and experience can be earned by killing lane creeps (see the third figure below), neutral creeps (see the fourth figure below), enemy heroes, and destorying enemy towers. As you can see in the third figure, lan creeps are divided into two factions, the Radient and the Dire, like the players. Lane creeps also come in groups. In the first 15 minutes of the game, each group of lane creeps consists of 3 melee creeps and 1 range creep. As the game processes, the quantity will increase. However, my analysis will only focus on the first 10 minutes of the game so we default the group size to be 4. The first wave of lane creeps spawns when the game timer counts down to 0. Then, a new wave spawns every 30 second. In each wave, one group of lane creeps will spawn for each lane and go down the lane (direction marked by black arrows in the map) towards the enemy ancient. Players from each team will kill the lane creeps to prevent them from destorying the towers as the creeps move towards the ancient, and to earn gold and experience. When the health (how much damage a creep can take before it dies) of a friendly lane creep is below a certain thresold, players can kill the friendly lane creep to prevent enemy players from getting gold and a portion of the experience. This action is called a deny. Neutral creeps spawn at specific sites in the jungle areas. The first wave of neutral creeps spawns at 1:00 (the 1 minute mark). Moreover, neutral creeps are neutral in the sense that they don’t belong to a specific team. Therefore, the deny machenism does not apply to jungle creeps. In most cases, neutral creeps would not continue to spawn like lane creeps unless they are killed by the players before the full minute mark.

Figure 4: The map of Dota2’s battle ground.

Figure 5: The towers. The left one is the Radient tower and the right one is the Dire tower.

Figure 6: The green creeps are Radient creeps and the red creeps are Dire creeps.

Figure 7: Neutral creeps.

As you probably have guessed, one of the ways to build advantage over the enemy team is to kill as many enemy creeps as possible and deny as many friendly creeps as possible. By doing so, players can maximize the gold and experience they earn while minimizing the gold and experience earned by the enemy players. This process is the major focus of the first 10 minutes of the match and since this process is carried out in lane (the top, mid, and bottom lane), the first 10 minutes is generally called the laning stage.

I usually play alone so in a public match, i.e., non-professional match, the match-making system will randomly match me with 4 teamates and 5 opponents based on my skill level. At my skill bracket, the team coordination and strategy execution are relatively weak. Therefore, whichever team that has the advantage after the laning stage is likely to win the game because the losing team usually can’t play as a team and figure out a strategy to shrink the gap and eventually make a comeback. Given that, my analysis will focus on my performance during the laning stage as a mid-lane player. I will assess my performance by the number of enemy creeps I kill and the number of friendly creeps I deny, item purchase decisions, item usage efficiency, rune controll, and rune usage.

A rune is an object that spawns in the game and there are 7 types of runes in total, the bounty rune, the arcane rune, the haste rune, the double damage rune, the regeneration rune, and the invisability rune. A player can either get his or her hero a temporary boost in power by picking up one of the 6 types of power runes or grant bonus gold to all players on the team by picking up a bounty rune. Runes can spawn at the four locations marked on the map. The top left and bottom right spots only spawn bounty runes. Each of the spots spawns a bounty rune at the beginning of the game, 0:00, and every 5 minutes afterwards. Only one of the middle two spots spawns a power rune. The first power rune spawns at 4:00. Then a new power rune spawns every 2 minutes. Keep in mind that the runes that were not picked up will disappear instead of ramaining on the map when the new runes spawn.

Figure 8: The map of Dota2’s battle ground.

Lane Efficiency

One of the most fundamental and basic mechanism of Dota2 is killing lane creeps, neutral creeps, and denying lane creeps to accumulate gold and experience yourself while preventing the opponent from getting the gold and experience. We will first look at the consistency of my ability to secure creep kills and denies during the laning stage. The number of creep kills and denies for each of those 20 games is shown in the figures below.

(#fig:lh_dn)This figure shows both the cumulative creeps kills and denies for each of my most recent 20 matchs. Match 1 is the most recent match. Match 20 is the least recent match. A triangle represents the number of creep kills. A dot represents the number of denies. Red points represent a win. Black points represent a loss.

As we can see my numbers of creep kills and denies were fairly consistent across the 20 matches, which means my performance was at least fairly consistent. However, were they consistenly bad, consistenly good, or consistenly average? To assess that, we need to revisite the creep spawning mechanism.

Recall that a group of creeps consists of 4 creeps in total. The first wave of creeps spawns at 0:00. Then, a new wave will spawn every 30 seconds. A simple caculation can show that, cumulatively and combining both Radient and Dire creeps, there would be 160 creeps going down each lane by 10:00, the end of laning stage. Therefore, in theory, a player could get 80 creep kills and 80 denies in lane.

However, that’s not possible in reality since players from the two teams would compete for creep kills and denies. Human are not robots (Actually, when competing with human players, even AI can’t get an 80/80 creep kills/denies). Even if one player is significantly better than the enemy player, the better player would still miss a portion of creep kills and denies due to human error and other factors such as leaving the lane to get a rune or leaving the lane to help teamates. Moreover, a deny is harder to get than a creep kill in general. Therefore, we shouldn’t expect an even distribution for creep kills and denies.

On the other hand, the neutral creeps spawns at each full minitue mark, excluding 0:00, assuming they are cleared by players each time. But in reality neutral creeps are usually not cleared every time. This mechanism makes the analysis a little bit tricky because we can’t reach a common number of total neutral creeps spawned for every match like the lane creeps. Moreover, the data doesn’t not distinguish lane creep kills and neutral creep kills. Therefore, it is better to aggregate lane creep kills and neutral creeps kills together as a single measure.

Following the practice of OpenDota, let’s assume the average highest realistic creep kills for a mid-lane player is 80 and the average highest realistic denies for a mid-lane player is 20. Let’s define lane efficiency:

A figure of my lane efficiency with the above assumptions is shown here:

Figure 9: This figure shows my lane efficiency of my 20 most recent matchs. Each dot represents the lane efficiency of a match. Red dot represents a win. Black dots represents a loss. The dotted line marks the average lane efficiency.

As we can see, for the majority of the matchs, my lane efficiency is consistently around 60.45% ranging from 50% to 70%, which means most of my performance is above the average. However, notice that there are 4 matchs where my lane efficiencies are below the average. Those four matchs share the same issue — I had a disadvantagous match-up, meaning the opponent hero’s strength matched my hero’s weakness so it was very hard for me to get lane creep kills and denies in lane. In order to improve, I should work on my understanding of the different match-up’s so I wouldn’t pick a hero that is bad against the opponent hero if I pick after the opponent player in the draftin stage, and practice to improve my mastery of the basic mechanism to ensure that I would not miss the lane creep kills and denies due to my error in addition to the already difficult match-up.

Another side of the consistency is that it signals that I have reached a plateau in my performance. The consistency is the call for change in general since my current stragety and skill don’t make me improve progressively and I am aware that there is plenty room for improvement.

Item Purchase and Usage

For the sake of simplicity, I will only analyze the purchase and usage for consumable regeneration items. A consumable regeneration item can be consumed to regenerate a hero’s health and mana. A hero’s health determines the maximum damage the hero can take before the hero dies. For example, ember spirit has 620 health to begin with, which means when an enemy hero deals 620 damage to ember spirit, he dies. A hero’s mana is consumed to use abilities. Using ember spirit as an example again, he starts with 315 mana. One of his abilities, sleight of fist, costs 50 mana to use once. Therefore, he can use that ability 6 times in total before he needs to regnerate his mana. The regeneration effect of some consumable regeneration items can be distrupted if your hero receives damage from a enemy hero. A table of all the comsumable regeneration items that can be purchased is presented here:

The last item, the bottle, is special because when all three charges are consumed, the bottle doesn’t disappear and players can replenish the 3 charges of the bottle by getting any kind of runes. You can think the bottle as a rechargable battery and the rune as a charging station. Another special thing about the bottle is that a player can use it to bottle a rune and use the rune later as oppose to consuming the rune immediately at the moment the player pick it up. This function has very important strategical value but I won’t dive into that here because I can wrote an entire blog on that. Instead, I will treat the bottle as a pure regeneration item.

The bottle is frequently bought by mid-lane players becuase the mid lane is closest to the two middle rune spawn sites that spawns a rune at 4:00 and every 2 minutes afterwards. Theoratically, if a player gets every power rune, 4 in total, and every bounty rune, except the 0:00 one, that spawns on the friendly side (marked by yellow points in the map), 2 in total, of the map in the first 10 minutes, the player would have 18 charges in total that can provide 2250 health regen and 1350 mana regen in total, assuming the regeneration effect was never distrupted.

Figure 10: Map.

However, you have to really dominate your lane to be able to get all those runes and that rarely happens. Moreover, it is unrealistic to assume that the regeneration effect was never disrupted. To analyze my bottle purchase decision and usage, We will look at a timeline of my bottle purchase and rune acquisition for one of the match where I purchased a bottle. When comparing the value of the bottle to other regneration items, I will make the assumption that the regneration effect of a distruptable item lasts 80% of the duration.

Figure 11: A timeline indicating when I purchased the bottle and when I got each rune.

By the end of the laning stage, I got 2 runes in total. Therefore, combining with the orignal 3 charges that came with the bottle, I had 9 charges. Based on our assumptions, each charge can regenerate 100 health and 60 mana, which makes the regeneration 900 health and 540 mana in total. We will compare the cost-effectiveness of the bottle, tango, healing salve, clarity and enchanted mango. The numer of each item required to regenerate 900 health and 540 mana and their respective cost is listed in the following table. Sine items can not be bought in portions, the quantity required is round up when necessary. For example, if 2.5 Healing Salve is required, we will make it 3.

To match the same amount of regeneration of the bottle, the best combiantion I could have got in terms of price is 3 sets of tango, 4 clarities, and 3 Healing Salve, 4 clarities. Although the combination of the tango and the clarity could be significantly cheaper and regenerate more health and mana, the amount of time it takes to complete the regeneration process makes this combination an invalid option since the regeneration rate per second of this combination is too low to keep up with the intense action of the mid lane. On the other hand, the combination of the healing salve and the clarity is 95 gold cheaper than the bottle, which might make this combination a valid purchase when I am in a match-up that is too hard, or even impossible, to get runes. However, the total regneration time required by the clarity, 120s, is significantly longer than that of the bottle, 22.5s, which would make it more likely for the enemy to distrupt my regeneration.

In my analysis, I made the assumption that all items is consumed to 80% of their maximum regeneration. However, the longer the regneration time per charge, the more likely it is for the enemy to disrupt the regneration effect. Therefore, in reality, 80% would be an over estimate for the amount of the healing salve and the clarity that is usually consumed. Even in the match represented in the above figure, where I only got two runes, the bottle had the advantage of fastest regneration time and the ability to bottle a rune for later consumption, with a fairly good price in comprison to other items. Moreover, the bottle becomes more valuable the more runes I get. Hence, as a mid-lane player, it should be always worth it to purchase a bottle unless I had a match-up where I have no hope of getting any rune at all. In that case, I might still purchase a bottle after the laning stage. As you can see in the timeline, I got 9 runes after the laning stage. The amount of regneration from the 9 runes alone made the bottle pay off itself, not to mention its stratigical value of bottling the rune.