Colonization

Colonization is revised in M&T. The new system keeps the old system except for one major change, a strict limit on colonial range. Then, we add a significant addition of an event-based expedition system. After unlocking expeditions from the third exploration idea, a regular event becomes available offering to send an expedition to a region of your choice. The places are unlocked based on your capital location and diplomatic technology level. When expeditions are sent they have a 40% chance of successful landing at their target area, which can be increased to 80% with the first colonialism idea. Otherwise they get one of the failure options which brings back nothing, maps, or maps and some ducats. Once it is determined an expedition successfully landed there is a calculation for which province it landed at, as described in Province Selection section. If all the provinces are owned then the owner of the province with the lowest score will get an event with the option to sell the province or defend it. If they choose to defend it then the chance of the expedition sender taking the province is their military tech level minus the province's defensive score divided by 10. After acquisition the sender can follow up with regular colonization nearby, conquest if there are countries there or send additional expeditions to the region. There is a decision unlocked with exploration ideas that shows on hover what dip tech you need to unlock certain expeditions, and reveals further decisions with more details on colonization for your game.

AI
AI pick expeditions based on weights for each expedition telling it how much to prefer sending that expedition compared to others. For example, the AI will prefer sending an expedition 4 times as much to Cuba than to Canada. Once an AI has a province in a region it is half as likely to send future expeditions there. This is to encourage spread of provinces to get trade sectors started up in many trade nodes. If the AI fails to takeover an already owned province it will become 90% less likely to send expeditions to that region for 20 years. This is to discourage the AI repeating expeditions to a region that will always fail due to military tech comparison.

Province Selection
On the day the expedition is due to finish it randomly selects a province in the region. If it is uncolonized that province is picked and selection ends. If it is already owned the province is scored according to the comparison formula and then a random province in the region is picked again. If the score is more favorable for the expedition sender than the previous score that province is saved as the new selected province. This repeats up to 10 times with the new province becoming the selected province if its score is better than the previous best score. Scoring only happens for owned provinces, and selection stops and picks the first uncolonized province.

Comparison Formula
Owner Mil Tech + 2 + (Province Fort Level * 2) [- 5 if colony] + Size bonus + Manpower bonus - Sender Mil Tech

Example: The province's defensive score is calculated by mil tech, plus defensive bonus which consists of 2 + 2 * fort level, minus 5 if colony, plus bonus depending on sum of taxed manpower in province by the state and all of the elites, plus bonus based on size of the province. If the expedition sender has mil tech 20 and the province defensive score is 15, and the owner decides to defend, the sender would have 50% chance of taking the province after landing. It is not directly 50% after landing because at worse odds owners are more likely to choose to sell the province than try to defend. Thus a 5 point advantage actually gives the sender approximately 64% chance of gaining a province after successfully landing.