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The Experience of Experience

A.K.A. more details than you ever wanted to know, about testing XCOM:UD 1.4 experience counters versus stat increases

My observations under Experience are getting incredibly long-winded. And at the same time, I am doing yet more research on it. So I've made this space to put levels of detail that are way more than a casual player is interested in. I will probably move some stuff out of Experience and over to here as I polish the info.

My Test Setup

For my testing, I have a MS Access VBA module that sucks in a savegame and compares it to another one (from before the combat). I edit experience counters (offsets 80-85 in UNITREF.DAT) and soldier stats (bytes 43-62 in SOLDIER.DAT) from a savegame ready to be ended (a Muton base with 16 soldiers standing in the entry area). Although it took weeks of futzing with Access to get it set up nicely, now that it's done, I can generate each combat-mission skill-point result in as quickly as I can load a savegame, end the mission, and then savegame on the geoscape (approx. 15 seconds). As of this writing, I have 4,544 individual soldier results (a.k.a. 284 savegame results at 16 soldiers each). This was for 11 different configurations of experience counters and soldier stats, as I zeroed in on different questions to ask (an average of about 25 savegames per configuration).

Psi Lab end-of-month increases vs. Psi Skill

FWIW, the Psi Lab training tests were way easier than combat-mission experience-vs.-skill-point tests. For three reasons: 1) I only had 16 soldiers in my base combat-mission scenario, whereas I could use all 250 soldiers when testing the Lab. (It took a lot of manual Soldier.Dat hacking, though!) 2) The Psi Lab results were much more simple and clear vs. combat results, as the wiki shows. Finally, 3) only one stat was being looked at, whereas combat results can affect 9 stats, each of which has to be examined in its own way. For the Psi Lab tests, I quickly generated 8,500 datapoints (34 savegames) and within just two different savegame configurations, it's behavior was crystal clear. (I didn't include these 8,500 results in the 4,544 counts I mentioned for combat results, of course.)

I'm happy to share my MS Access setup with anybody that wants it; just send me an email. But you are warned - it's all home grown code. I'll walk you through it, but you have to do it exactly right... there ain't no user manual or Help routines for this baby! You coders know what I mean. Also, just so you know... the only thing it does relative to game files, is read Soldier.Dat. It doesn't touch any other file, and it doesn't write to anything (except itself, of course). I did all my Soldier and Unitref hacking by hand.

FWIW, at first I used Hex Workshop to hack Soldier and Unitref (thanks Danial!), but lately I've only been using EDIT... I couldn't figure out a way to make HW "remember" where to place its structure overlays, and it's a hassle to place them back on all 16 soldiers every time I use it. (If anybody knows a way to get HW to remember where they should be placed, let me know!) In the long run, I find it easier to just scroll through Soldier or Unitref with EDIT. Either way is real work, but at least with EDIT, it's "just show me the #$@!$ bytes!" I also wish HW had a wider data view (with smaller fonts for it) and would let you re-arrange the fields shown in the structure overlay in whatever order you want (i.e., one that makes more sense for my purposes than their somewhat scattered layout).

Testing Skill Point Increase

For anyone who's interested in testing combat mission experience vs. resulting skill point increases:

You only need to edit the experience counters in UNITREF, and the soldier stat values in SOLDIER. That is to say, XCOM does not carry the soldier stat values in UNITREF back to the geoscape... it just re-reads them out of SOLDIER. So stats in UNITREF are "read only" (for that combat only) and lost when combat ends. The "Kills" variable is the only value I know of in UNITREF that's directly carried forward into the geoscape, although other things like experience counters (for skill increase) and health (for hospitalization) indirectly carry forward / affect values in the geoscape.

Another Look at Primary Point Increases

Here's another way to look at primary stat increases:

  Sorted on Number of Actions        Sorted on AvePtInc/Actions

        Average       AvePtInc/               AvePtInc/
Actions Pt.Inc. Delta  Actions        Actions  Actions
    1    +0.5   +0.5    +0.500            3     +0.667
    2    +0.5     -     +0.250            1     +0.500
    3    +2.0   +1.5    +0.667            4     +0.500
    4    +2.0     -     +0.500            6     +0.417
    5    +2.0     -     +0.400            5     +0.400
    6    +2.5   +0.5    +0.417           11     +0.364
    7    +2.5     -     +0.357            7     +0.357
    8    +2.5     -     +0.313            8     +0.313
    9    +2.5     -     +0.278            9     +0.278
   10    +2.5     -     +0.250            2     +0.250
   11    +4.0   +1.5    +0.364           10     +0.250

Average Point Increase (Ave.Pt.Inc.) shows the average number of primary skill points earned relative to primary actions taken. Delta shows the difference in skill points earned, from one action to the next. Note that many actions are "wasted" in the sense they cause no further skill points - unless, of course, you get all the way to the next breakpoint. This is especially critical when only a limited number of actions are available to your crew (i.e., only so many shots aliens can take before they're all dead). Finally Average Point Increase Per Actions Taken is the Average Point Increase divided by Actions for that same row. When the table on the left is sorted on this latter column (on the right), you can more clearly see how e.g. 10 actions is a bad idea, unless it gets you to 11. (And anything over 11 is truly wasted.) Note that 1 or 2 actions did not actually earn the expected 0.5 points in my testing - see next section.

Non-Randomness in Primaries

This section only applies to primary skill increases:

When I've talked about experience rolls, I've made it sound like you always get the average (halfway between the ranges). But this is definitely not the case, especially when there are very few experience points (EPs) in UNITREF offsets 80-85. Specifically, when there are only 1 or 2 primary actions - the first 'step' for primary skill points - I saw very weird, non-random stuff. Example: I would set up 16 soldiers, with only 1 or 2 EPs for each soldier. When I ended the combat, the skill point range was undeniably 0-1. But far more often than not, the 16 soldiers in my test crew would all get 0 skill points, all across the board. Then every now and then they would all get 1 skill point, all across the board. And even less often, there would be a mix of 0s and 1s in the results. The actual average increase was about 0.33 points, not the 0.5 points I wrote in Experience. (Individual stat averages for first step: Psi Skill 0.18, Firing Acc 0.53, Reactions 0.18, Throw Acc 0.81, Melee Acc 0.19; average across all: 0.33. This is with 400-900 samples per stat average.) To this day, I cannot get a handle on what is triggering them to all be 0 or 1. It's not influenced by total experience counters, number of other types of experience gained, or secondary points awarded. My best guess is that it is based on some high-level bit mask over the system clock, because it seems to come and go in unpredictable spurts. (If this is true, it's possible that my DosBox wrapper is messing with the results. But then, it would be for anyone using DosBox.) Then again, stuff that comes and goes in unpredictable spurts could be almost anything. I did my testing by reloading and combat-ending only about a dozen different hacked combat-mission savegames (as I zeroed in on issues to test) hundreds of times in sum total, so I can never be sure my problems weren't caused by the simple fact that I was reloading a few games many times, instead of racking up experience points au natural, where some unknown randomness seed might be being kept / ticked away.

Anyway, I kept the main wiki summary simple, and just strongly advised people to try to get at least three primary actions. Although 1-2 actions was weird, by 3 actions I saw little non-randomness. More precisely, I saw some non-randomness, such as all stats getting the exact same result for several tests in a row. Melee was oddly low at its third step, averaging 1.99 instead of 2.5 (n=744). But in general, when summarized across any larger n (100+ datapoints), the summary stats were almost always very close to the expected average of the range. So, there was a little bit of weirdness at 3+ actions... but it was nothing like at 1-2 actions.

Secondary "Steps"

In the wiki on secondary stats, I said that there is an even slope for secondary skill point gains, from an average of 4 (range 0-8) at (hacked) secondary level 0, to an average of 1 (range 0-2) at Cap-1. That was a simplification, to keep the wiki short. In actuality, it's like this:

The three stats TUs, Health, and Strength have a maximum range that increases by 1 at every increment of 10, working backward from the cap. Stamina - that high-winded beast - increases at multiples of 15. This follows the usual X-COM approach of defining a range and rolling randomly within it. So a graph of the maximum range of points possible vs. current stat level looks like this:

Thus e.g. TUs has a range max of 2 from stat level 71-79 (80 is the cap), 3 from 61-70, 4 from 51-60, etc. TUs, Health, and Strength work backward in increments of 10, but Stamina has steps 15 stat points wide. So it has a range max of 2 from stat level level 86-99, 3 from 71-85, etc.

(All secondary skills have a range minimum of 0 across their span; it's entirely possible to not get an increase in a secondary skill after a combat. So on average, you expect to get half the range maximum.)

Interestingly, at (hacked) stat level=0, Stamina and Health can get 8 points assigned (like I said in the wiki), but Strength can get 9 points, and TUs can get 10. Then all of them quickly drop the range to 1 point less, at level=1 (except Stamina, working backwards in steps of 15).

So this step function means that the "even slope" I talked about is not quite correct, nor are the averages that I put in that table for each level (those are based on a linear slope equation instead of half of that step's range maximum, which is what the true case is). Still, it's a very good simplification, especially when you're talking about the average number of CMs to go from e.g. Recruit Max to Cap. So I kept the wiki shorter by not going into the level of detail shown here.

Tips on Increasing Skills

Here are more tips (too much detail for the wiki!) for increasing stats with the popular "firing squad" tactic. For anyone not familiar with it, here's how it works. First, you have to have good psi soldiers in powered/flying armor. Then:

Mind control all the aliens, and gather them in one spot
Line up your guys a la a firing squad
Give one or two aliens a laser pistol
Kill everybody via reaction shots with something weak like the standard-issue pistol

This has the advantage of increasing psi, firing, and reaction skills all at once. The weak pistol lets you make more hits before you kill them; only hits count toward Firing Accuracy increase (not Kills per se). Mutons are by far the best for this, because they are relatively thick skinned but mainly because they have a ton of hit points. And their friends the silacoids are almost (but not quite) invulnerable to the little popgun at higher difficulty levels than Beginner, due to higher alien armor levels (see Kill Modelling).

Some tips, then. Veteran players will know most of these (except the first one), but newbies may not:

Notice that the standard pistol carries 12 rounds - and that it takes 11 actions to get the best roll possible (2-6) for a skill increase. So if your soldiers have shot a full clip, stop having them react-fire, and let other guys who haven't used up their clip (or haven't had a go at all yet) shoot. (Or stop them when they have 1 bullet left, if you want.) Reaction firing counts toward a Reaction increase even if you miss, so counting bullets is an easy way to track it. Once they've used a clip, it's time to let low Firing-Accuracy guys get 3 or 11 non-reaction, sure hits (the primary-skill breakpoints) to increase their Firing Accuracy. That is, if you haven't been keeping tracking of everybody's hits (a challenging thing to do).
If some of your soldiers have very low reaction levels (less than 50, or especially less than 40), others are liable to shoot before them. In severe situations, all aliens may be killed before your low-reaction guys fire at all. Assuming you want to build their reaction skill(!), make sure low-reaction guys do get to fire off their whole clip, even if they're the last one with any bullets left in the firing squad. They're the ones that need it most. There's no rush with larger UFOs (see the Alien Deployment counts for UFOs)... Mutons take approx. 13 hits to kill at Beginner difficulty level, and 34 hits at higher levels (see Kill Modelling). Or let your low-reaction guys shoot first, if it won't take much to kill all the targets. In the long run, consider rejecting recruits with Reaction under 50 or especially 40. (You'll have plenty of money by the time you've got good Psi.)
Oddly, every now and then, your soldiers will get a higher reaction experience count, than reaction shots they have made. I've seen soldiers with 15 in Unitref[80] when they had only reaction-shot one clip of 12 bullets. The extra counts occur right when an alien dies (or is knocked unconcious), in a situation where more than one of your soldiers could've reaction fired. Apparently all your soldiers's reactions are "queued" and the next guy's reaction counter is ticked before it checks whether the alien is still up. It only happens if there's an extra guy's reaction queued who didn't get to fire, so the more guys you have, the more likely it is that the alien won't be killed or knocked out by the last guy shooting. Thus, you have the potential to get extra reaction counts up to the number of aliens killed, although just who will get them (if you have a lot of shooters) is anybody's guess. Unless you peak at Unitref and see exactly who did get it. There's not much you can do with this factoid, but there it is. Update: Additional limited testing shows that soldiers with lower reactions (relative to others shooting) tend to get the extra Reaction experience. This supports the idea that it's a reaction queue at work - soldiers with lower reactions will be toward the end of the queue, and more likely to have an alien killed before they shoot.
If you're really serious about increasing skills as evenly as possible, you can put aliens up for execution one at a time. And if you're insanely serious, it can be mano a mano versus one soldier at a time. This is the best way to keep track of number of hits your guys have made. But it's incredibly tedious work and can take a grueling hour or more vs. mutons. It's WAY funner to just line everybody up and let the lead fly!
If you are counting hits, it's easier if you have some distance to your target and a wide open space behind them. (Not against a wall or the edge of the map.) This way, some of your misses will clearly keep going past the target. With a wall or map edge, though, it can be harder to tell what hit and what didn't. (And if you're right next to them, you sometimes miss into the ground, which can be hard to judge as a hit or miss.)
Perversely, it's easier to hit, if you're right next to the target. Due to how, even though there are stated accuracies, etc., if you're right next to them, even calculated misses may very well still intersect them. But it will also be harder to detect if you missed because you'll e.g. shoot directly into the ground sometimes. Shrug.
If you have a lot of Mutons lined up, you don't need to worry about some of the above. Especially reaction shots... all of your crew should easily be able to get 11+ reactions. Half your crew should be able to get 11+ hits, especially if you do the next item, to make sure you spread them evenly...
The truly dedicated can save the game and peek at the UNITREF experience counters, offsets 80-85. As long as you don't hack the file, it ain't cheating. It's a sure way to know exactly how folks are doing, including for psi. Just be sure to close your hex editor before saving your game! Otherwise the editor may "lock" the file and it won't actually be written (but XCOM won't complain!). Maybe I'll make an applet that reads them on demand... anyone interested?
Along these lines, shots do count as hits (to increase Firing Accuracy) if your soldier aimed/reacted at one alien, but hit another. Any hit on any alien counts.
But of course, not if they're currently mind controlled. They are considered "friendlies" then, and hits on friendlies don't increase your score. So don't mix MC'd with non-MC'd aliens, if some of your guys are liable to reaction fire on un-friendlies. Either MC everybody or nobody, in that case.
Another reason to MC all aliens or none, is because uncontrolled aliens will target MC'd aliens. They know who has the least armor, making for their best shot - and it'll be friendly aliens, all of whose armor is less than your power/flying armor.
One way to avoid reaction shots by your guys into a mixed crowd of non/MC'd aliens, is to turn your shooters around for a turn. And a way to (sometimes) keep an MC'd alien from shooting unfriendly ones, is to turn that alien around. And possibly just MC the aliens right next to him, blocking the view of farther, enemy ones (if they're all in a line).
It's said that powered armor and flying suits are safe from laser pistols. This is only partly true. Laser pistols (LPs) do an average of 46 laser damage, but this can be up to twice as high (92). XCOM armor is as follows:

            Front  Sides  Rear  Under
 Coveralls    12     8      5      2 
 Personal     50    40     30     30 
 Powered     100    80     70     60 
 Flying      110    90     80     70

As you can see, even the sides of Flying Armor can take damage from a LP (although only ~2% of the time, and very light damage at that). LP shots in the back won't give you a deep wound (up to 12 damage), but they can put you in the hospital for a week or three. So be careful, especially about moving so as to turn your back (giving an alien a reaction shot). They WILL target your back or under armor! They know where your weaknesses are.
Be careful of using silicoids, celatids, and other critters with built-in weapons for reaction-fire target practice. Sometimes they won't shoot you, but you never know! Get them out of the way first with directed fire by low FA guys. (And keep track of their hits!) Psst: Did you know the celatid has a very limited range?
Large aliens (sectopods, reapers, and cyberdiscs) do weird things when MC'd. You're only MC'ing one-fourth of them, so the rest "takes over" and basically, it's not MC'd. (Has anybody ever tried MC'ing all four quarters??) You wouldn't want to try it with sectopods and cyberdiscs (cuz they can shoot), but with the floaters' pet reaper, you can still use them for target practice. You just have to keep moving reapers farther away than they can run to you, each round. And hope your hits land on their non-MC'd quarters. (Maybe you should MC their butt instead of their head, since they'll run toward you??) I haven't actually tested this vs. the experience counter, but I presume it's true. You can probably get a lot of reaction-fire experience (even on a floater mission - floaters die like flies), since it will take many pistol shots to take down a reaper at long distance.

7Saturn (talk) 10:30, 14 September 2015 (EDT) The fun part is, that you still can do another MC on one of the remaining parts and get their starting stats again. So in essence, you can let them run four times as far, as if conventional MC of the whole unit took place. But partial MC will not keep a Cyberdisc or Sectopod from shooting itself or any other of your units, when reaction fire triggering kicks in. MC'ing their butt instead of their head won't help that, as it's not about the used graphics but the part that is being controlled. The upper right corner will stay MCed, even when you turn the unit. So better wait until it's the next round for you, if you want to have a clear shot. This also means, you can make a Cyberdisc or a Sectopod shoot itself. As they don't make a very good training unit this way, shooting them is rather usefull, especially with sectopods, as they have autoshot. Take care, none of your soldiers is near, as Cyberdiscs explode and Sectopods will finish their auto shot, even when kill by the very first shot. So the remaining shots might end up, where you don't want them to.

You might have considered stun-rodding (SRing) aliens, to increase your Melee Accuracy. Then, revive them to SR again, or shoot. But the SR can put up to 65 unconscious points on them, which can take forever to revive with a medkit (or even use up all your med supplies without being revived). So Melee Accuracy is not a very viable skill to develop. We'd all much rather build our Firing Accuracy and Reaction, than this ~~obtuse~~ irrelevant-in-UFO skill! It might be more important in TFTD, though.
In case you hadn't noticed - Aliens that have no weapons and have nowhere to go within one turn that's out of your line of sight, rarely move at all (except to turn/look around sometimes). Which is to say, you don't have to MC them if you don't want to (or don't need any more psi experience) - they aren't going anywhere. But keep in mind that if they see just one of you, they know where all your men are. And so they always know if there is anywhere that even one of them can go run and hide. The sneaky little sh$ts!
Enemy units never get fatal wounds - but friendly units can. And MC'd aliens are considered friendly. So if you accidentally hit MC'd aliens, you have to check them for wounds. (Yet another reason to MC all or none, so you don't reaction-fire into a pack of mixed ones.) Here's where I got another of XCOM's many little "surprises": I was marching a lot of aliens back to their base's exit zone while they still had their weapons. (So they could drop their stuff in the zone, and I could withdraw and come back and milk the base again.) I accidentally forgot to MC one (hard to see in a big pack of MC'd guys) and all he had left on him was a grenade. So of course he chucks the grenade, which bounces off the MC'd guys and comes to rest right in the middle of the pack. This 1) destroyed every bit of loot that had been dropped, 2) killed a couple of aliens (including himself) and gave most of the other Mutons 2-3 fatal wounds, plus many lost a lot of health (=skill point training down the tubes), and finally 3) when all the gear got destroyed, there wasn't a single weapon left that I could use to shoot some Elerium out of a Power Source. (I only had pistols, since they always have Heavy Plasmas.) Damn, was I cussing a mean streak, kicking myself! LOL

Psi Testing

I've made a separate page for notes on my Psi Testing, here.

Base Design Scratch Pad

Scratch pad for base designs, using NKF's design tool. Also see X-COM Base Module Pix and Base_Layout_Strategy. Possible entries:

dirt  
lift
lab
workshop
psi
containment
storage
quarters
small_radar
large_radar
hyperwave
grav
mind
missile
laser
plasma
fusion
hangar1
hangar2
hangar3
hangar4

Turn Sequencing

Mike, the problem with making the turn sequencing it's own page is that some of that in theory. My actual patience for testing is very low(the person who does that lives about thirty minutes away from me, actually). But if you think it's worth a page, I'll put it down. Reply when able. (Actually, I recently thought that the 'Anyone Alive' check might be performed not for BOTH sides each turn, but only after that side's turn. This would explain why, after you kill all the aliens, you see the alien turn screen briefly after ending the X-Com turn. Similar if the aliens off all the soldiers during the Alien turn.) Arrow Quivershaft 19:54, 10 October 2007 (PDT)

Get better soon, man! Arrow Quivershaft 02:04, 1 November 2008 (CDT)

User talk:MikeTheRed

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