V8 drop rate study


 * This is an ongoing study. Results may change as new data is processed.

The "golden rule" that players have to keep a certain number of specific cards they need is one of the most persistent beliefs among players. While it has been proven wrong for part cards, players object that it may still be valid for engines.

Assumptions
As the environment for the test also allows to check several other hypotheses, they have been included. The following hypotheses are tested:


 * 1) Cards come to those who have them. The game grants less of a card if players don't have some of them in their inventory.
 * 2) Cards for events are always limited. The game grants less of a card during events requiring the card.
 * 3) Drop rates are dependent on a player's garage. The game grants less of a card if the player has vehicles that need them.
 * 4) Drop rates decrease for recently upgraded vehicles. The game grants less of a card that has recently been used to upgrade a vehicle.

Test
To verify if there are such mechanisms, one test player contributing to WikiProject Statistics kept his inventory constantly void of V8 Engines, while all other players continued normally. Before the experiment, the test player also opened all pending and used up the engines so that there were no V8 Engines "hidden" in dedicated boxes either.
 * 1) As soon as a Pro Kit Box dropped a V8 Engine, it was immediately used to upgrade a vehicle before opening the next box. This ensures that the criteria for hypothesis 1 are met.
 * 2) During the test period, the player participated in the Bentley Continental GT3 Championship, the Koenigsegg Regera R&D and the Koenigsegg CCXR Trevita Championship. All three cars require V8 Engines, so the situation allows to test hypothesis 2.
 * 3) The player's garage contained 33 vehicles requiring V8 Engines that were not upgraded to pro level. If hypothesis 3 was true, the game should grant significantly less V8 Engines.
 * 4) When a V8 Engine was dropped, it was used to upgrade the Mercedes-Benz SLK 55 AMG, the Ferrari 308 GTS and the Spada Codatronca TSS which only require 1 engine per upgrade level. Thus, there was always at least one V8 vehicle that had recently been upgraded, fulfilling the requirement of hypothesis 4.

The sample for this test was the database of WikiProject Statistics which has been evaluated from July 25, 2019, to [ongoing]. The observed Pro Kit Boxes were Daily Kit Box, Engine Box, Extra Box, Finish Line Box, Multiplayer Pro Box, Optimal Shuffle Box, Optimal Split Box, Random Box, Starter Box, and Ultra Box which are the most common ones.

If the assumptions were true, the test player should encounter a significantly lower drop rate of V8 Engines than the other players. If this was the case, more specific experiments would have to be performed to test which of the four hypotheses caused the decrease.

Temporary results
The table to the right shows the frequency of V8 Engines in relation to all obtained engines.

Temporary results until September 14, 2019:

Cards come to those who have them
There were no V8 Engines in the test player's inventory during the whole study. The assumption is wrong.
 * 9.46 % of the test player's engines were V8.
 * 7.18 % of the other players' engines were V8.

Cards for events are always limited
Test player: Other players: The assumption is wrong.
 * 10.29 % of the engines during events were V8.
 * 7.87 % of the engines outside events were V8.
 * 6.95 % of the engines during events were V8.
 * 7.41 % of the engines outside events were V8.

Drop rates are dependent on a player's garage
At the start, the test player's garage contained 33 vehicles requiring V8 Engines that were not at pro level. During the study, the number decreased to 31 because the player received so many V8 Engines that two of the vehicles had reached pro level. Despite this, the number of vehicles requiring V8 Engines was very large all the time. The assumption is wrong.
 * 9.46 % of the test player's engines were V8.
 * 7.18 % of the other players' engines were V8.

Drop rates decrease for recently upgraded vehicles
There was always at least one V8 vehicle in the test player's garage that had recently been upgraded. The assumption is wrong.
 * 9.46 % of the test player's engines were V8.
 * 7.18 % of the other players' engines were V8.

Conclusion
All four assumptions are wrong.