What follows is my attempt to help players in choosing and understanding their AI opponents. In CIV III, THE single most important factor for any AIs overall performance is the value of their start location and the immediate vicinity. That said, given a sufficient number of games there are certain trends that begin to bear themselves out. All things being about equal (start location, river access, resource availability, ect) the AIs will perform differently. There are 2 primary reasons for this; their traits and their Unique Unit – the former being far more important on average. Unlike the human player, AI play is wholly scripted and therefore incapable of making the proper adjustments to changing situations. As such, certain traits lend themselves better to the scripted play of the AI than others, and thus produce the ‘on average’ better performance of some AI civs over others. Let me state from the onset, that the observations that follow are just that – ‘observations’ – and not hard and true outcomes to be expected in any particular game.
The Best of the Best (they rarely disappoint):
Agricultural Civs – the AI will typically begin building a settler with no regard to whether their food/growth output is sufficient enough for the settler to actually be produced within the number of turns the pop-growth/shield output dictates. An AI city waiting innumerable turns without actually building anything is a common site – its simply waiting for the food/pop-growth ratio to catch up to the point where it can finally crank out a settler. The Agri trait mitigates this flaw by giving the AI the extra food/growth bonus that allows for more rapid settler production than other AIs. The net result is a trend for Agri Civs to outperform other civs in expansion – and thus establish themselves more dominantly early.
Scientific Civs – while Scientific may rate low among human players, it certainly helps the AI. The scientific trait gives the AI that slight little boost that keeps it ahead of the other AIs in research – that slight boost is later accentuated by the faster production of half-priced libraries. That ‘freebie’ tech at the beginning of each age given by scientific is far more beneficial to the AI than the human, and often cements the scientific AIs position of dominance over the other AIs upon entering the Industrial Age. Great Wonders are also far more beneficial to the AI than the human, thus the higher chance of a SGL helps the AI as well. The net result is that these AIs will typically have the tech lead and the consequent overall gold lead that brokering these techs gives them. Lastly, there are an unusually high number of the better UUs possessed by the 9 scientific AIs (Hoplite, Immortal, Enkidu, Droman, Sipahi, Cossack, Bab-Bowman), which tends to give them yet another advantage.
Industrious Civs – in previous versions of CIV III (prior to C3C) this trait stood alone in a category by itself. So, profound was the advantage of this trait for both AI and human player alike! This is no longer the case; the toning down of the worker speed from a 100% to 50% advantage has brought industrious back to earth. Nevertheless, the trait still helps the AI greatly. The bottom line is this – the AIs never-ever build anywhere near enough workers. As a consequence their reliance on the few workers that they do build is huge. The industrious civs faster workers go a long way towards addressing the AIs unwillingness to build more workers. Further, Industrious civs that lose 1 or 2 early on are not as devastated as other civs. The higher shield output of the typical Industrious AI will manifest itself throughout the entire game. Lastly, a few of the Industrious civs actually have the ‘build often’ checked for workers – this may also result in greater overall worker numbers.
The Runner Ups (boon or bust)
Expansionist Civs – typically come out of the starting gate as good or better than other traits. Translating their goody hut/ barbarian advantage into early tech leads and quite often, faster city expansion. A sprawling Expansionist AI by the mid-Middle Ages is common. Unfortunately, from my experience, in spite of their larger size, Expansionist AIs tend to have no staying power and are slowly picked apart from the mid-game on. The factors here are 3-fold; a typically higher than an average aggression level resulting in more wars and thus slowing their infrastructure building, a higher than average number of ultra-early Golden Ages that boost their early age but is for the most part wasted, and lastly the fact that 5 of the 8 expansionist civs are paired with traits that the AI plays poorly. On average outstanding in the first 6 rounds of the boxing match – but without an early knockout (quick overrun of multiple neighbors) – it gets winded fast and craps out at the end.
Religious Civs – are hard to measure. The lower the difficulty level the greater the value of the AI being religious. The reason is simple; prior to Monarch level the AI does NOT receive any bonus in reducing anarchy turns during government transitions. Changing governments is a favorite AI past time, doing so FAR too often through the course of a game. 3 to 5 government transitions in lower level games can greatly retard non-religious AI power. On the other hand, at the upper levels religious AIs are only slightly (if at all) faster in recovering from anarchy. The AI is hampered by the fact that it will NOT use the luxury slider to compensate for any happiness issues. The result is a higher than necessary number of ‘entertainers’ in their most productive cities. Religious AIs tend to be happier AIs due to the cheaper temples and cathedrals. As a consequence it has been my experience that IF they survive, they tend to develop a more solid infrastructure from the mid-game on and become more formidable in the late game. AI performance with religious tends to run the extreme ends from terrific to horrendous.
Commercial Civs – like religious civs tend to run the extreme ends of performance as well, but even more so. The AI cannot use this trait to its best advantage except by sheer accident. It has no concept of the advantage of a huge commercial/communist empire with its lower OCN. A commercial AI rarely translates its inherent gold advantage out properly, far too often the commercial AI acts like 19-year-old, pro-athlete with his first million-dollar check – he wastes it. However, the trait works as a terrific amplifier – making those AIs with the ‘best of the best’ traits that much more formidable, while doing little to nothing for the ‘artificially ignorant’ traits. Take a little test; run 10 continents games against the Iroquois or Greece – then run 10 more against India or England with the exact same starting positions – enough said.
Artificial Ignorance (subtlety is NOT an AI strength)
Seafaring – is a trait that in the hands of the human is as deadly as any. Unfortunately in the hands of the AI – the results are staggering underperformance. The Seafaring advantage of an extra movement point at sea is wasted by an AI that will NEVER attempt a suicide run to find another land mass, an AI that WILL build a good sized fleet and then retreat nearly every unit back to port that loses even a single hit point, an AI that may field a huge ground force – and yet invades with a mere fraction of the force required for successful amphibious operations. Outside of arch maps – seafaring makes the AI appear to be ignorant to the point of the ridiculous. The subtle play as well as the far range strategic planning required to make seafaring work are simply beyond the AIs programming.
Militaristic – is seafaring’s ugly twin sister. The ability to generate 2 or 3 early great leaders by a human player may result in a game breaking moment! For an AI it means 2 GLs used to rush a temple and a library, with the 3rd used for an army loaded with 1 defensive unit and 1 offensive unit doing garrison duty in a small town! Yes, yes – from time to time the AI will actually field an Army and may even accidentally use it well – but those times are as rare as a white rhino. The early archer rush spring-boarded by those cheaper barracks, the pillaging strat, the artillery red-line strat, selective elite unit use – all of these are all beyond the AIs ability, and while this effects all the AIs militaristic or not – it especially effects the performance of the AIs whose traits is supposedly geared to benefit from war. Here again is a trait that requires subtlety and far range planning to make-work – both are beyond the AI.
The AI & UUs
The AI loves to escort units and to bring a great number of defensive units with any offensive force. The result is a much higher than average use of defensive units in offensive roles as compared to a human player – with defensive units having a greater value for the AI than the human. Secondly, the AI is big on having a heavy number of garrison units in each and every one of its cities – the result is once again a greater focus on defensive units and a greater value to the AI than the human. The AI handles offensive units very poorly due to the ‘piecemeal’ method in which it attacks. This lack of ‘concentration of forces’ gives the AIs with the defensive UUs an edge over the offensive AI UUs. The last category are the ‘specialty’ UUs, those requiring subtle play, planning, or an indirect approach to maximize effectiveness: in this the AI is an abject failure – completely wasting a UU like the Hwach’a (the AI has no concept of proper artillery use), and making terrible use of UUs like the Jaguar, Chasqui, Beserk and Man O’ War.
The Strongest AIs
Unlike the human player that has successfully engaged in early wars – the AI does not benefit nearly as much – initially. The reason is that AI vs AI wars are ‘wars of attrition’ – they last far longer than human wars, and take a tremendous toll on the AIs including the winning AI! Having put all their builds and commerce into unit production; it often leaves their infrastructure building well behind that of other AIs, a large trade debt, their military reduced to a fraction of what they need, and commonly they are well behind the other AIs in tech research. So in spite of they’re having the largest total city count, they are far from the strongest civ. What this means for the human player is that your typical method of choosing the AI to go to war with (the – whose the highest AI in total score method) is quite often the wrong approach. You will find more often than not that that nice, and until now, peaceful mid-sized AI 3rd or 4th on the score list – is often the single most dangerous AI in the game. Their infrastructure is deep, their units numerous and up to date, and their ability to form alliances from an unsullied reputation is still strong. Keep this in mind when trying to assess who the most powerful AIs really are. Naturally, you can not lose sight of the fact that that much larger AI, given a long enough period to recuperate – will catch up to and eclipse all the other AIs.
Conclusion: Let me repeat it one more time: “In CIV III, THE single most important factor for any AIs overall performance is the quality of their start location and the immediate vicinity.” However, my personal experience playing numerous games against every civ has lead me to certain conclusions; the more direct and obvious the benefit of the trait the better the AI will perform on average, the more subtle the trait the worse the AI will perform. The more defensive the UU the better the AI handles it – if the UU requires anything other than a ‘direct’ approach to be used well – the AI will bungle it. Unlike its human counterpart the AI is almost always incapable of ‘coming back from behind.’ For the AIs, the rich get richer and the poor get poorer with each passing turn. While both the AI and human share in the advantages of the ‘REX’ traits like Agri/Ind/Exp they part ways to varying degrees with the other 5 traits. Last but not least, do not forget that the AI plays the game strictly ‘one turn at a time’ re-computing its strategy each and every turn. In essence it has no real ‘strategy’.