In Civilization VI and its expansions, a project can be undertaken in the Production queue of a city to provide some sort of benefit which doesn't include creating a permanent feature like a unit, building, or District.
There are now three main types of projects:
- City projects, which are more or less the same as in previous games. They are required to unlock some powerful feature, such as nuclear weapons, or perform some empire-wide task, such as launching spacecraft. They may (usually) be undertaken in all your cities (with the exceptions of the Science Victory projects, which always require an active Spaceport in the city), and usually need be completed only once. Their Production cost is fixed. You should undertake these projects only on a need-to-do basis; otherwise, you will be wasting Production capacity.
- District projects, which are closely related to the new districts and Great People. They convert a city's Production into other kinds of yields while the project is active and (usually) provide points toward earning Great People when it ends. They can be undertaken as many times as a player wants in any city that has the requisite district. The Production cost of district projects scales up from a base price based on the number of technologies and/or civics a player has discovered, but this also means that their overall effectiveness goes up (as the points they produce are a function of their Production cost). District projects are a decent way to boost some specific yields for a time (city production is converted each turn into the project yield type at a rate of 15%), and also to accelerate your progress towards attracting a coveted Great Person (when completed most district projects provide 15% of the project cost as great people points). District projects will not award great people points if the Great People class is banned by the World Congress Patronage resolution.
- Gathering Storm adds a third type of project: competition projects. These become available in all cities only after a resolution to start a Scored Competition in the World Congress has been enacted, and turn a city's Production toward increasing the player's score for the competition. The projects have fixed Production costs and are only unlocked while the relevant competition lasts. You should undertake them if you're interested in winning the relevant competition, but should always consider the other opportunities for increasing your score as well.
The various types of projects and their effects are listed here.
District Projects Great People yield formula
- GPP = D_TYPE * (1 + 7 * DEVELOPMENT_RATIO)
- where D_TYPE is: 10 for most district projects, 5 for Theater Square Performances and Carnival and 30 for Occult Research
- where DEVELOPMENT_RATIO is a number between 0 and 1, equal to the higher of: number of unlocked tech divided by number of techs OR number of unlocked civics divided by number of civics
- Formula example for Campus Research Grants:
- 44/61 civics unlocked -> ratio is 0.721
- 50/77 tech unlocked -> ratio is 0.649
- using 0.72 since it is higher -> 10 * (1 + 7 * 0.721) = 60 GPP per project completion (Scientist)
- Formula example for Theater Square Performances:
- 21/61 civics unlocked -> ratio is 0.344
- 33/77 tech unlocked -> ratio is 0.428
- using 0.42 since it is higher -> 5 * (1 + 7 * 0.428) = 20 GPP per project completion (Writer, Artist, Musician)
While the District Project production cost is scaled by Game Speed, the Great People yield is not (most likely an oversight since the cost to recruit a great person is scaled by speed). For example, Campus Research Grants convert approximately 22% of production to Great Scientist points on Standard speed, but less than 15% on Epic speed (even though the project cost is 50% higher).
This means that District Projects are more efficient for Online and Quick game speeds and less efficient for Epic and Marathon speeds.