Alien Stats

By Zombie

Most of the tabes listed on this page can be downloaded here. (18kb Excel Worksheet).

From the surface, alien stats seem like a straight-forward idea. As most of us know, there are 5 skill levels to the game and as the difficulty increases, so do enemy stats. Why then do most stat listings around the net only cover one? Even worse, the guides which show all skill levels have values which are unsubstantiated and/or just pull the OSG's (Official Strategy Guide, by David Ellis) numbers at face value. Perhaps it is just easier to blindly copy information than it is to verify.

In any event, the X-COM community deserves better. For this reason, I set out on a long journey to gather all the stats at each skill level one summer day. Six months and countless hours later, I had the data. Unfortunately, this was only for the Collector's Edition of the game. What about the other versions though? Collecting stats from them would be possible, just not practical. There had to be a better (and faster) way.

Core Stats

Thanks to some research by a few forum members, it was determined that alien stats reside in the executable. Not only that, but there is only one set of numbers, not five. This had a couple of important implications:

Comparing stats between versions was now possible and easy.
Because there is only one set of alien stats, it must mean that a skill level stat is calculated directly off this "core" or base group.

After checking the executables of as many game versions as possible, all the alien stats matched. Therefore, any information presented here will apply to your version of the game! Here then, are the base values:

Core alien statistics

Alien Race/Rank	TU	Sta	He	Br	Rea	FA	TA	Str	PST	PSK	Fr	L/R	Re	Un	EnR	VPS	Agg	Mel	Int
Floater Soldier	50	90	35	80	50	50	58	40	35	0	8	6	4	12	30	12	2	70	4
Floater Navigator	50	90	35	80	50	50	58	40	35	0	8	6	4	12	30	14	2	70	5
Floater Medic	50	90	35	80	50	50	58	40	35	0	8	6	4	12	30	16	1	70	6
Floater Engineer	50	90	35	80	50	50	58	40	35	0	8	6	4	12	30	18	2	70	7
Floater Leader	55	95	40	80	60	60	58	47	40	0	16	12	8	12	30	25	0	70	8
Floater Commander	60	100	45	80	66	63	65	48	45	0	24	18	12	16	30	35	0	76	8
Sectoid Soldier	54	90	30	80	63	52	58	30	40	0	4	3	2	2	30	10	2	76	3
Sectoid Navigator	54	90	30	80	63	52	58	30	40	0	4	3	2	2	30	12	2	76	4
Sectoid Medic	54	90	30	80	63	52	58	30	40	0	4	3	2	2	30	14	1	76	5
Sectoid Engineer	54	90	30	80	63	52	58	30	40	0	4	3	2	2	30	16	2	76	6
Sectoid Leader	54	90	30	80	63	52	58	30	50	50	4	3	2	2	30	20	1	76	7
Sectoid Commander	54	90	30	80	63	52	58	30	50	60	4	3	2	2	30	25	0	76	8
Snakeman Soldier	40	80	45	80	45	58	65	47	40	0	20	18	16	12	30	15	2	54	2
Snakeman Navigator	40	80	45	80	45	58	65	47	40	0	20	18	16	12	30	17	2	54	3
Snakeman Engineer	40	80	45	80	45	58	65	47	40	0	20	18	16	12	30	20	2	54	4
Snakeman Leader	40	80	45	80	55	65	65	47	45	0	20	24	22	20	30	28	2	54	5
Snakeman Commander	45	84	55	80	65	58	65	47	50	0	26	26	22	20	30	36	2	54	6
Ethereal Soldier	68	96	55	80	75	74	80	48	50	40	35	35	35	35	40	20	1	85	6
Ethereal Leader	68	96	55	80	75	74	80	48	60	45	40	40	40	40	40	30	1	85	7
Ethereal Commander	68	96	55	80	75	74	80	48	65	50	45	45	45	45	40	40	1	85	8
Muton Soldier	56	90	125	80	60	54	62	70	25	0	20	20	20	10	40	15	2	78	2
Muton Navigator	56	90	125	80	60	54	62	70	25	0	24	24	24	15	40	17	2	78	3
Muton Engineer	56	90	125	80	60	54	62	70	25	0	28	28	28	20	40	19	2	78	4
Reaper	62	90	148	90	64	0	0	90	35	0	28	28	28	4	34	25	2	80	2
Chryssalid	110	140	96	100	70	0	0	110	50	0	34	34	34	34	40	25	2	80	4
Silacoid	40	80	114	100	40	0	0	70	80	0	50	50	50	10	40	20	2	80	3
Celatid	70	90	68	90	40	100	0	70	60	0	20	20	20	20	40	20	2	80	4
Sectopod	62	90	96	110	64	60	0	90	100	0	145	130	100	90	50	30	1	80	4
Cyberdisc	62	90	120	110	64	60	0	90	100	0	34	34	34	34	50	20	1	80	5

Key
TU	Time Units
Sta	Stamina
He	Health
Br	Bravery
Rea	Reactions
FA	Firing Accuracy
TA	Throwing Accuracy
Str	Strength
PST	Psionic Strength
PSK	Psionic Skill
Fr	Front Armor
L/R	Left/Right Armor
Re	Rear Armor
Un	Under Armor
EnR	Energy Recharge
VPS	Victory Points
Agg	Aggression
Mel	Melee
Int	Intelligence

Skill Level Stats

Below you will find the stats to each skill level.

Beginner skill level stats

Alien Race/Rank	TU	Sta	He	Br	Rea	FA	TA	Str	PST	PSK	Fr	L/R	Re	Un	EnR	VPS	Agg	Mel	Int
Floater Soldier	50	90	35	80	50	25	58	40	35	0	4	3	2	6	30	12	2	70	4
Floater Navigator	50	90	35	80	50	25	58	40	35	0	4	3	2	6	30	14	2	70	5
Floater Medic	50	90	35	80	50	25	58	40	35	0	4	3	2	6	30	16	1	70	6
Floater Engineer	50	90	35	80	50	25	58	40	35	0	4	3	2	6	30	18	2	70	7
Floater Leader	55	95	40	80	60	30	58	47	40	0	8	6	4	6	30	25	0	70	8
Floater Commander	60	100	45	80	66	31	65	48	45	0	12	9	6	8	30	35	0	76	8
Sectoid Soldier	54	90	30	80	63	26	58	30	40	0	2	1	1	1	30	10	2	76	3
Sectoid Navigator	54	90	30	80	63	26	58	30	40	0	2	1	1	1	30	12	2	76	4
Sectoid Medic	54	90	30	80	63	26	58	30	40	0	2	1	1	1	30	14	1	76	5
Sectoid Engineer	54	90	30	80	63	26	58	30	40	0	2	1	1	1	30	16	2	76	6
Sectoid Leader	54	90	30	80	63	26	58	30	50	50	2	1	1	1	30	20	1	76	7
Sectoid Commander	54	90	30	80	63	26	58	30	50	60	2	1	1	1	30	25	0	76	8
Snakeman Soldier	40	80	45	80	45	29	65	47	40	0	10	9	8	6	30	15	2	54	2
Snakeman Navigator	40	80	45	80	45	29	65	47	40	0	10	9	8	6	30	17	2	54	3
Snakeman Engineer	40	80	45	80	45	29	65	47	40	0	10	9	8	6	30	20	2	54	4
Snakeman Leader	40	80	45	80	55	32	65	47	45	0	10	12	11	10	30	28	2	54	5
Snakeman Commander	45	84	55	80	65	29	65	47	50	0	13	13	11	10	30	36	2	54	6
Ethereal Soldier	68	96	55	80	75	37	80	48	50	40	17	17	17	17	40	20	1	85	6
Ethereal Leader	68	96	55	80	75	37	80	48	60	45	20	20	20	20	40	30	1	85	7
Ethereal Commander	68	96	55	80	75	37	80	48	65	50	22	22	22	22	40	40	1	85	8
Muton Soldier	56	90	125	80	60	27	62	70	25	0	10	10	10	5	40	15	2	78	2
Muton Navigator	56	90	125	80	60	27	62	70	25	0	12	12	12	7	40	17	2	78	3
Muton Engineer	56	90	125	80	60	27	62	70	25	0	14	14	14	10	40	19	2	78	4
Reaper	62	90	148	90	64	0	0	90	35	0	14	14	14	2	34	25	2	80	2
Chryssalid	110	140	96	100	70	0	0	110	50	0	17	17	17	17	40	25	2	80	4
Silacoid	40	80	114	100	40	0	0	70	80	0	25	25	25	5	40	20	2	80	3
Celatid	70	90	68	90	40	50	0	70	60	0	10	10	10	10	40	20	2	80	4
Sectopod	62	90	96	110	64	30	0	90	100	0	72	65	50	45	50	30	1	80	4
Cyberdisc	62	90	120	110	64	30	0	90	100	0	17	17	17	17	50	20	1	80	5
Zombie	40	110	84	110	40	0	0	84	80	0	4	4	4	4	20	18	2	80	3
Civilian	35	65	30	80	30	30	50	20	5	0	0	0	0	0	20	0	0	50	1

Experienced skill level stats

Alien Race/Rank	TU	Sta	He	Br	Rea	FA	TA	Str	PST	PSK	Fr	L/R	Re	Un	EnR	VPS	Agg	Mel	Int
Floater Soldier	52	93	35	80	53	53	58	40	36	0	8	6	4	12	30	12	2	72	4
Floater Navigator	52	93	35	80	53	53	58	40	36	0	8	6	4	12	30	14	2	72	5
Floater Medic	52	93	35	80	53	53	58	40	36	0	8	6	4	12	30	16	1	72	6
Floater Engineer	52	93	35	80	53	53	58	40	36	0	8	6	4	12	30	18	2	72	7
Floater Leader	57	98	40	80	63	63	58	47	41	0	16	12	8	12	30	25	0	72	8
Floater Commander	62	104	45	80	69	66	65	48	46	0	24	18	12	16	30	35	0	79	8
Sectoid Soldier	56	93	30	80	66	55	58	30	41	0	4	3	2	2	30	10	2	79	3
Sectoid Navigator	56	93	30	80	66	55	58	30	41	0	4	3	2	2	30	12	2	79	4
Sectoid Medic	56	93	30	80	66	55	58	30	41	0	4	3	2	2	30	14	1	79	5
Sectoid Engineer	56	93	30	80	66	55	58	30	41	0	4	3	2	2	30	16	2	79	6
Sectoid Leader	56	93	30	80	66	55	58	30	52	52	4	3	2	2	30	20	1	79	7
Sectoid Commander	56	93	30	80	66	55	58	30	52	62	4	3	2	2	30	25	0	79	8
Snakeman Soldier	41	83	45	80	47	61	65	47	41	0	20	18	16	12	30	15	2	56	2
Snakeman Navigator	41	83	45	80	47	61	65	47	41	0	20	18	16	12	30	17	2	56	3
Snakeman Engineer	41	83	45	80	47	61	65	47	41	0	20	18	16	12	30	20	2	56	4
Snakeman Leader	41	83	45	80	58	68	65	47	46	0	20	24	22	20	30	28	2	56	5
Snakeman Commander	46	87	55	80	68	61	65	47	52	0	26	26	22	20	30	36	2	56	6
Ethereal Soldier	70	99	55	80	79	78	80	48	52	41	35	35	35	35	40	20	1	88	6
Ethereal Leader	70	99	55	80	79	78	80	48	62	46	40	40	40	40	40	30	1	88	7
Ethereal Commander	70	99	55	80	79	78	80	48	67	52	45	45	45	45	40	40	1	88	8
Muton Soldier	58	93	125	80	63	57	62	71	26	0	20	20	20	10	40	15	2	81	2
Muton Navigator	58	93	125	80	63	57	62	71	26	0	24	24	24	15	40	17	2	81	3
Muton Engineer	58	93	125	80	63	57	62	71	26	0	28	28	28	20	40	19	2	81	4
Reaper	64	93	148	90	67	0	0	91	36	0	28	28	28	4	34	25	2	83	2
Chryssalid	114	145	96	100	74	0	0	112	52	0	34	34	34	34	40	25	2	83	4
Silacoid	41	83	114	100	42	0	0	71	83	0	50	50	50	10	40	20	2	83	3
Celatid	72	93	68	90	42	106	0	71	62	0	20	20	20	20	40	20	2	83	4
Sectopod	64	93	96	110	67	63	0	91	104	0	145	130	100	90	50	30	1	83	4
Cyberdisc	64	93	120	110	67	63	0	91	104	0	34	34	34	34	50	20	1	83	5
Zombie	40	110	84	110	40	0	0	84	80	0	4	4	4	4	20	18	2	80	3
Civilian	35	65	30	80	30	30	50	20	5	0	0	0	0	0	20	0	0	50	1

Veteran skill level stats

Alien Race/Rank	TU	Sta	He	Br	Rea	FA	TA	Str	PST	PSK	Fr	L/R	Re	Un	EnR	VPS	Agg	Mel	Int
Floater Soldier	54	97	35	80	56	56	58	41	37	0	8	6	4	12	30	12	2	75	4
Floater Navigator	54	97	35	80	56	56	58	41	37	0	8	6	4	12	30	14	2	75	5
Floater Medic	54	97	35	80	56	56	58	41	37	0	8	6	4	12	30	16	1	75	6
Floater Engineer	54	97	35	80	56	56	58	41	37	0	8	6	4	12	30	18	2	75	7
Floater Leader	59	102	40	80	67	67	58	48	43	0	16	12	8	12	30	25	0	75	8
Floater Commander	64	108	45	80	73	70	65	49	48	0	24	18	12	16	30	35	0	82	8
Sectoid Soldier	58	97	30	80	70	58	58	31	43	0	4	3	2	2	30	10	2	82	3
Sectoid Navigator	58	97	30	80	70	58	58	31	43	0	4	3	2	2	30	12	2	82	4
Sectoid Medic	58	97	30	80	70	58	58	31	43	0	4	3	2	2	30	14	1	82	5
Sectoid Engineer	58	97	30	80	70	58	58	31	43	0	4	3	2	2	30	16	2	82	6
Sectoid Leader	58	97	30	80	70	58	58	31	54	54	4	3	2	2	30	20	1	82	7
Sectoid Commander	58	97	30	80	70	58	58	31	54	64	4	3	2	2	30	25	0	82	8
Snakeman Soldier	43	86	45	80	50	64	65	48	43	0	20	18	16	12	30	15	2	58	2
Snakeman Navigator	43	86	45	80	50	64	65	48	43	0	20	18	16	12	30	17	2	58	3
Snakeman Engineer	43	86	45	80	50	64	65	48	43	0	20	18	16	12	30	20	2	58	4
Snakeman Leader	43	86	45	80	61	72	65	48	48	0	20	24	22	20	30	28	2	58	5
Snakeman Commander	48	90	55	80	72	64	65	48	54	0	26	26	22	20	30	36	2	58	6
Ethereal Soldier	73	103	55	80	84	82	80	49	54	43	35	35	35	35	40	20	1	91	6
Ethereal Leader	73	103	55	80	84	82	80	49	64	48	40	40	40	40	40	30	1	91	7
Ethereal Commander	73	103	55	80	84	82	80	49	70	54	45	45	45	45	40	40	1	91	8
Muton Soldier	60	97	125	80	67	60	62	72	27	0	20	20	20	10	40	15	2	84	2
Muton Navigator	60	97	125	80	67	60	62	72	27	0	24	24	24	15	40	17	2	84	3
Muton Engineer	60	97	125	80	67	60	62	72	27	0	28	28	28	20	40	19	2	84	4
Reaper	66	97	148	90	71	0	0	93	37	0	28	28	28	4	34	25	2	86	2
Chryssalid	118	151	96	100	78	0	0	114	54	0	34	34	34	34	40	25	2	86	4
Silacoid	43	86	114	100	44	0	0	72	86	0	50	50	50	10	40	20	2	86	3
Celatid	75	97	68	90	44	112	0	72	64	0	20	20	20	20	40	20	2	86	4
Sectopod	66	97	96	110	71	67	0	93	108	0	145	130	100	90	50	30	1	86	4
Cyberdisc	66	97	120	110	71	67	0	93	108	0	34	34	34	34	50	20	1	86	5
Zombie	40	110	84	110	40	0	0	84	80	0	4	4	4	4	20	18	2	80	3
Civilian	35	65	30	80	30	30	50	20	5	0	0	0	0	0	20	0	0	50	1

Genius skill level stats

Alien Race/Rank	TU	Sta	He	Br	Rea	FA	TA	Str	PST	PSK	Fr	L/R	Re	Un	EnR	VPS	Agg	Mel	Int
Floater Soldier	56	100	35	80	59	59	58	42	39	0	8	6	4	12	30	12	2	78	4
Floater Navigator	56	100	35	80	59	59	58	42	39	0	8	6	4	12	30	14	2	78	5
Floater Medic	56	100	35	80	59	59	58	42	39	0	8	6	4	12	30	16	1	78	6
Floater Engineer	56	100	35	80	59	59	58	42	39	0	8	6	4	12	30	18	2	78	7
Floater Leader	61	106	40	80	70	70	58	49	44	0	16	12	8	12	30	25	0	78	8
Floater Commander	67	112	45	80	77	74	65	50	50	0	24	18	12	16	30	35	0	85	8
Sectoid Soldier	60	100	30	80	74	61	58	31	44	0	4	3	2	2	30	10	2	85	3
Sectoid Navigator	60	100	30	80	74	61	58	31	44	0	4	3	2	2	30	12	2	85	4
Sectoid Medic	60	100	30	80	74	61	58	31	44	0	4	3	2	2	30	14	1	85	5
Sectoid Engineer	60	100	30	80	74	61	58	31	44	0	4	3	2	2	30	16	2	85	6
Sectoid Leader	60	100	30	80	74	61	58	31	56	56	4	3	2	2	30	20	1	85	7
Sectoid Commander	60	100	30	80	74	61	58	31	56	67	4	3	2	2	30	25	0	85	8
Snakeman Soldier	44	89	45	80	53	68	65	49	44	0	20	18	16	12	30	15	2	60	2
Snakeman Navigator	44	89	45	80	53	68	65	49	44	0	20	18	16	12	30	17	2	60	3
Snakeman Engineer	44	89	45	80	53	68	65	49	44	0	20	18	16	12	30	20	2	60	4
Snakeman Leader	44	89	45	80	64	76	65	49	50	0	20	24	22	20	30	28	2	60	5
Snakeman Commander	50	94	55	80	76	68	65	49	56	0	26	26	22	20	30	36	2	60	6
Ethereal Soldier	76	107	55	80	88	87	80	50	56	44	35	35	35	35	40	20	1	95	6
Ethereal Leader	76	107	55	80	88	87	80	50	67	50	40	40	40	40	40	30	1	95	7
Ethereal Commander	76	107	55	80	88	87	80	50	72	56	45	45	45	45	40	40	1	95	8
Muton Soldier	62	100	125	80	70	63	62	74	28	0	20	20	20	10	40	15	2	87	2
Muton Navigator	62	100	125	80	70	63	62	74	28	0	24	24	24	15	40	17	2	87	3
Muton Engineer	62	100	125	80	70	63	62	74	28	0	28	28	28	20	40	19	2	87	4
Reaper	69	100	148	90	75	0	0	95	39	0	28	28	28	4	34	25	2	89	2
Chryssalid	123	156	96	100	82	0	0	116	56	0	34	34	34	34	40	25	2	89	4
Silacoid	44	89	114	100	47	0	0	74	89	0	50	50	50	10	40	20	2	89	3
Celatid	78	100	68	90	47	118	0	74	67	0	20	20	20	20	40	20	2	89	4
Sectopod	69	100	96	110	75	70	0	95	112	0	145	130	100	90	50	30	1	89	4
Cyberdisc	69	100	120	110	75	70	0	95	112	0	34	34	34	34	50	20	1	89	5
Zombie	40	110	84	110	40	0	0	84	80	0	4	4	4	4	20	18	2	80	3
Civilian	35	65	30	80	30	30	50	20	5	0	0	0	0	0	20	0	0	50	1

Superhuman skill level stats

Alien Race/Rank	TU	Sta	He	Br	Rea	FA	TA	Str	PST	PSK	Fr	L/R	Re	Un	EnR	VPS	Agg	Mel	Int
Floater Soldier	58	104	35	80	62	62	58	43	40	0	8	6	4	12	30	12	2	81	4
Floater Navigator	58	104	35	80	62	62	58	43	40	0	8	6	4	12	30	14	2	81	5
Floater Medic	58	104	35	80	62	62	58	43	40	0	8	6	4	12	30	16	1	81	6
Floater Engineer	58	104	35	80	62	62	58	43	40	0	8	6	4	12	30	18	2	81	7
Floater Leader	63	110	40	80	74	74	58	50	46	0	16	12	8	12	30	25	0	81	8
Floater Commander	69	116	45	80	81	78	65	51	52	0	24	18	12	16	30	35	0	88	8
Sectoid Soldier	62	104	30	80	78	64	58	32	46	0	4	3	2	2	30	10	2	88	3
Sectoid Navigator	62	104	30	80	78	64	58	32	46	0	4	3	2	2	30	12	2	88	4
Sectoid Medic	62	104	30	80	78	64	58	32	46	0	4	3	2	2	30	14	1	88	5
Sectoid Engineer	62	104	30	80	78	64	58	32	46	0	4	3	2	2	30	16	2	88	6
Sectoid Leader	62	104	30	80	78	64	58	32	58	58	4	3	2	2	30	20	1	88	7
Sectoid Commander	62	104	30	80	78	64	58	32	58	69	4	3	2	2	30	25	0	88	8
Snakeman Soldier	46	92	45	80	55	71	65	50	46	0	20	18	16	12	30	15	2	62	2
Snakeman Navigator	46	92	45	80	55	71	65	50	46	0	20	18	16	12	30	17	2	62	3
Snakeman Engineer	46	92	45	80	55	71	65	50	46	0	20	18	16	12	30	20	2	62	4
Snakeman Leader	46	92	45	80	68	80	65	50	52	0	20	24	22	20	30	28	2	62	5
Snakeman Commander	52	97	55	80	80	71	65	50	58	0	26	26	22	20	30	36	2	62	6
Ethereal Soldier	78	111	55	80	93	91	80	51	58	46	35	35	35	35	40	20	1	98	6
Ethereal Leader	78	111	55	80	93	91	80	51	69	52	40	40	40	40	40	30	1	98	7
Ethereal Commander	78	111	55	80	93	91	80	51	75	58	45	45	45	45	40	40	1	98	8
Muton Soldier	64	104	125	80	74	66	62	75	29	0	20	20	20	10	40	15	2	90	2
Muton Navigator	64	104	125	80	74	66	62	75	29	0	24	24	24	15	40	17	2	90	3
Muton Engineer	64	104	125	80	74	66	62	75	29	0	28	28	28	20	40	19	2	90	4
Reaper	71	104	148	90	79	0	0	97	40	0	28	28	28	4	34	25	2	92	2
Chryssalid	127	162	96	100	86	0	0	118	58	0	34	34	34	34	40	25	2	92	4
Silacoid	46	92	114	100	49	0	0	75	92	0	50	50	50	10	40	20	2	92	3
Celatid	81	104	68	90	49	124	0	75	69	0	20	20	20	20	40	20	2	92	4
Sectopod	71	104	96	110	79	74	0	97	116	0	145	130	100	90	50	30	1	92	4
Cyberdisc	71	104	120	110	79	74	0	97	116	0	34	34	34	34	50	20	1	92	5
Zombie	40	110	84	110	40	0	0	84	80	0	4	4	4	4	20	18	2	80	3
Civilian	35	65	30	80	30	30	50	20	5	0	0	0	0	0	20	0	0	50	1

From the tables above it quickly became apparent that some stats change while others do not. The ones which never change are:

Health
Bravery
Throwing Accuracy
Energy Recharge
Victory Points
Aggression
Intelligence
Most other stats

The stats which do change are:

Time Units
Stamina/Energy
Reactions
Strength
Psionic Strength
Psionic Skill
Melee
Firing Accuracy
Armor

Calculating Skill Level Stats from the Core

"How exactly are the changing stats calculated?" That was the big question on my mind while looking at the data. First I compared Beginner against Experienced. A ratio between the two stat levels yielded a rough percentage, but in order to nail it down exactly a comparison between all the skill levels was necessary. What I came up with was rather surprising; most stats increase with a constant percentage while a couple stats are strange. The stats which change by constant percentage include:

Time Units: 4%
Stamina/Energy: 4%
Reactions: 6%
Strength: 2%
Psionic Strength: 4%
Psionic Skill: 4%
Melee: 4%

Those which are different include:

Firing Accuracy: Beginner level FA is one-half the core value, while Experienced through Superhuman recieve a 6% increase per level.
Armor: Beginner level aliens have one-half the core value while higher difficulty levels stay at the core with no improvement per level.

To arrive at an equation linking the core to the different skill levels required a little creative thinking on my part. Since the Beginner skill level numbers match the core group exactly, no modification is necessary. For this reason, I assumed the modifier would be 0 for the lowest skill level and something simple (think: integer) for the higher levels. Turns out, this was a valid theory which led me to introduce a new term in the equation to bridge skill levels called the Skill Level Multiplier, or SLM for short.

SLM values

Beginner: 0
Experienced: 1
Veteran: 2
Genius: 3
Superhuman: 4

With this last piece of data in-hand I was able to formulate a generalized equation to describe the stats which change and have Beginner levels equal to the core.

Skill Value = INT(Core Value * (100 + (Percentage * SLM)) / 100)

As an example, let's assume we want to find the number of Time Units a Superhuman Chryssalid has. The core TU for the Chryssalid is 110 while the percentage is 4% and the Skill Level Multiplier is 4. Now it is just a matter of substituting these values into the equation:

Superhuman TU = INT(110 * (100 + (4 * 4)) / 100)
                        = INT(110 * (100 + 16) / 100)
                        = INT(110 * 116 / 100)
                        = INT(12760 / 100)
                        = INT(127.60)
                        = 127

This number agrees with the Chryssalid's TU during an actual Superhuman mission. (Note: The "INT" function is a necessary part of the equation because it models how the game handles numbers with decimals. Since X-COM was programmed using declared variables as Integer to save space, the INT function serves as the liaison between a real-world calculation and a number given in the game. Therefore, fractional parts of the number are dropped or truncated).

Strange and Interesting Facts

Zombie stats are not listed in the executable where the normal aliens are situated. Not only that, but their stats do not change as the skill level increases. For more information on this oddity, see the Editing Alien Stats heading on this page.
Civilian stats are also constants and do not change.
Chryssalids which are spawned in a mission by the game have stats modified in the normal way. However, Chryssalids which hatch from Zombies have all their stats set to their core, irregardless of current difficulty level. For instance, a normal Superhuman Chryssalid has 127 TU while a Superhuman Chryssalid hatched from a Zombie has only 110 TU! Apparently the game neglects to modify the stats during a mission.

A Word About The Official Strategy Guide

Alien Stats (Characterestics) start on pg 249 and continue to pg 260. The Beginner Skill level is fine except for a few small errors. However, at the higher difficulty levels the OSG's data falls far short of expectations. I have a suspicion the author failed to recognize what effect integer rounding would play or wasn't privy to the exact equation. In any event, be aware that the OSG's alien stat tables should not be used due to massive errors. The information presented here supersedes that from the OSG through rigorous tests.

What the Mind Probe and Psi-Amp Don't Tell You

Often, during the heat of a battle, you may decide to use the Mind Probe or Psi-Amp to look at an alien's stats. These devices really only touch the tip of the iceberg in terms of what is possible to know. And although Soldier and Tank attributes can be accessed directly, they have the same limitations placed on them as the aliens. This is due to the fact that only so much information can be presented on one screen.

Below is a table of the data which isn't normally shown. Note: For stats which change due to skill level such as Melee and Psi, the core values are given. Also, psionic stats will only be shown in-game when Psionic Skill is > 0. Most units have no skill in this area and thus have missing stats.

Unseen stats

Alien Race/Rank	Mel	EnR	St	Kn	Flt	Dmf	PSk	Pst	Msb	VPS	Agg	Int
Floater Soldier	70	30	21	16	2	1	0	35	4	12	2	4
Floater Navigator	70	30	21	16	2	1	0	35	4	14	2	5
Floater Medic	70	30	21	16	2	1	0	35	4	16	1	6
Floater Engineer	70	30	21	16	2	1	0	35	4	18	2	7
Floater Leader	70	30	21	16	2	1	0	40	4	25	0	9
Floater Commander	76	30	21	16	2	1	0	45	4	35	0	8
Sectoid Soldier	76	30	16	12	0	1	0	40	3	10	2	3
Sectoid Navigator	76	30	16	12	0	1	0	40	3	12	2	4
Sectoid Medic	76	30	16	12	0	1	0	40	3	14	1	5
Sectoid Engineer	76	30	16	12	0	1	0	40	3	16	2	6
Sectoid Leader	76	30	16	12	0	1	50	50	3	20	1	7
Sectoid Commander	76	30	16	12	0	1	60	50	3	25	0	8
Snakeman Soldier	54	30	18	18	0	5	0	40	4	15	2	2
Snakeman Navigator	54	30	18	18	0	5	0	40	4	17	2	3
Snakeman Engineer	54	30	18	18	0	5	0	40	4	20	2	4
Snakeman Leader	54	30	18	18	0	5	0	45	4	28	2	5
Snakeman Commander	54	30	18	18	0	5	0	50	4	36	2	6
Ethereal Soldier	85	40	20	15	0	6	40	50	4	20	1	6
Ethereal Leader	85	40	20	15	0	6	45	60	4	30	1	7
Ethereal Commander	85	40	20	15	0	6	50	65	4	40	1	8
Muton Soldier	78	40	21	16	0	7	0	25	4	15	2	2
Muton Navigator	78	40	21	16	0	7	0	25	4	17	2	3
Muton Engineer	78	40	21	16	0	7	0	25	4	19	2	4
Reaper	80	34	23	16	0	10	0	35	4	25	2	2
Chryssalid	80	40	21	16	0	9	0	50	4	25	2	4
Silacoid	80	40	10	10	0	8	0	80	4	20	2	3
Celatid	80	40	12	12	6	1	0	60	4	20	2	4
Sectopod	80	50	23	16	0	11	0	100	4	30	1	4
Cyberdisc	80	50	15	15	2	12	0	100	4	20	1	5
Zombie	80	20	18	18	0	13	0	80	4	18	2	3
Civilian	50	20	21	16	2	1	0	5	4	10	0	1
Tank	70	50	16	16	0	4	0	100	30	20	2	3
Hovertank	70	50	12	12	6	4	0	100	30	20	2	3

Melee (Mel): All units have this ability but only the Reaper, Chryssalid, Silacoid and Zombie can use it. The melee value is a percentage used to calculate the base chance of "hitting" the target.
Energy Recharge (EnR): Determines how fast a unit recovers Energy (aka Stamina) lost through movement during a round.
Standing Height (St): Standing height of the unit.
Kneeling Height (Kn): Kneeling height of the unit. Only X-COM soldiers can kneel so technically this stat goes unused for the aliens.
Floating Height (Flt): Determines how high the unit is above the ground. Celatids and Hovertanks are the high-fliers at 6 units while the Floater and Cyberdisc are ground-huggers at 2 units. Surprisingly, Civilians actually float, but you never notice this on a mission.
Damage Modifier (Dmf): This number represents a category each unit uses for determining the susceptiblity to weapons in the game.
Psionic Skill (PSk): Most units have no Psionic Skill and therefore are unable to wage psionic attacks. Sectoid Leaders and Commanders have this ability as do all Ethereals. If you are lucky enough to capture and interrogate one of these aliens your soldiers can also get this ability through training.
Psionic Strength (Pst): A number between 0 and 100 which indicates how well a unit can use and resist psionic attacks.
Motion Scanner Blip Size (Msb): For every tile a unit moves, it gets this value added to a counter in unitref.dat. The bigger the number, the bigger the blip the Motion Scanner will show.
Victory Points (VPS): Points received when you kill that unit.
Aggression (Agg): A rating of 0-2 which determines how aggressive an alien is. High ranking aliens have low aggression while the "grunts" get the higher numbers.
Intelligence (Int): A number between 2 and 8 which indicates how long an alien will remember the location of a unit once spotted.

Editing Alien Stats

If you have a Geoscape and Tactical executable, alien stats start at non-offset byte 379,729 in the Geoscape. The CE version has a single unified executable called "UFO Defense" in which the alien stats start at non-offset byte 480,145. Both have 33 records of 39 bytes each.

Byte	Represents	Values	Unitref	Zombie†
0	Race	3-16	[000]	17
1	Rank	0-7	[042]	7
2	Movement Type	0	[011]	0
3	Flying	0-1	DNA	0§
4	Time Units	35-110	[025]	40
5	Health	30-148	[026]	84
6	Stamina	65-140	[027]	110
7	Reactions	20-75	[028]	40
8	Strength	20-110	[017]	84
9	Firing Accuracy	0-100	[023]	0
10	Throwing Accuracy	0-80	[024]	0
11	Melee	50-85	[056]	80
12	Front Armor	0-145	[029]	4
13	Left Armor	0-130	[030]	4
14	Right Armor	0-130	[031]	4
15	Rear Armor	0-130	[032]	4
16	Under Armor	0-100	[033]	4
17	Health Recharge	0	[034]	0
18	Energy Recharge	20-50	[035]	20
19	MCD Index	0	?	0
20	Armor Recharge	1	[036]	1‡
21	Inventory Layout	0	[046]	0
22	Loftemps Index 1	2-5	[048]	3
23	Loftemps Index 2	2-5	[052]	3
24	Standing Height	10-23	[049]	18
25	Kneeling Height	10-18	[050]	18
26	Floating Height	0-6	[051]	0
27	Damage Modifiers	1-12	[055]	13
28	Psionic Skill	0-60	[037]	0
29	Psionic Strength	5-100	[057]	80
30	Bravery	0-3	[059]	0
31	Motion Scanner Size	3-30	[061]	4
32	Unit Lighting	0-1	[071]	0
33	Light Direct	0	[075]	0‡
34	Corpse Type	50-79	[038]	57
35	Size	0-1	DNA	0§
36	Victory Points	10-40	[039]	18
37	Aggression	0-2	[044]	2
38	Intelligence	1-8	[073]	3

Record	Alien/Unit
1	Floater Soldier
2	Floater Navigator
3	Floater Medic
4	Floater Engineer
5	Floater Leader
6	Floater Commander
7	Reaper Terrorist
8	Sectoid Soldier
9	Sectoid Navigator
10	Sectoid Medic
11	Sectoid Engineer
12	Sectoid Leader
13	Sectoid Commander
14	Snakeman Soldier
15	Snakeman Navigator
16	Snakeman Engineer
17	Snakeman Leader
18	Snakeman Commander
19	Ethereal Soldier
20	Ethereal Leader
21	Ethereal Commander
22	Muton Soldier
23	Muton Navigator
24	Muton Engineer
25	Tank
26	Male Civilian
27	Female Civilian
28	Chryssalid Terrorist
29	Silacoid Terrorist
30	Celatid Terrorist
31	Sectopod Terrorist
32	Cyberdisc Terrorist
33	Hovertank

† This column represents the theoretical stats for the Zombie which may or may not be found in the executable. All stats were collected by looking at unitref offsets which should hold.
§ Flying ability and size information are not found in unitref, but we can safely derive them through logic.
‡ These values do not have a corresponding unitref offset but since all the aliens have the same value it should be safe to assume the Zombie inherits them too.
All the unknowns have now been identified, but five of them need a little explanation. They are summarized below.

Byte 2: Corresponds to Unitref[011]. Always 0. It is a movement type for units: 0=Walking, 1=Sliding, 2=Flying which is never used properly.
Byte 17: Corresponds to Unitref[034]. Always 0. It was supposed to be a health recharge modifier, but the game ignores any values.
Byte 20: Corresponds to Unitref[036].. Always 1. It was supposed to be an armor recharge modifier but it's possible the game ignores this.
Byte 32: Corresponds to Unitref[071]. Unit lighting, X-COM units are all 16, everything else is 0 except for Cyberdisc which is 1 (odd!).
Byte 33: Corresponds to Unitref[075]. Always 0 & unused by game. Called "lightdirect", with values of 0=all around, 1=direction unit facing possibly for mobile light sources which were not implemented.

Additional Stats

The following information is found in the UFO Defense executable starting at non-offset 447,868 consisting of 8 records having 20 bytes each. Or if you have the DOS version, it can be found in tactical.exe starting at 391,278. These stats are mainly the in-built weapon turrets for tanks and aliens. Accuracy and TU costs are given as percentages.

Unit	Damage Type	Ammo Type	Damage	Snap Acc.	Snap TU's	Auto Acc.	Auto TU's	Aim Acc.	Aim TU's	Blaster Eff?
Tank/Cannon	0	4	60	60	33	0	0	90	80	0
Tank/Rocket Lnchr	2	12	85	55	45	0	0	115	75	0
Tank/Laser Cannon	3	17	110	50	33	0	0	85	75	0
Hovertank/Plasma	4	36	110	86	30	0	0	100	60	0
Hovertank/Launcher	2	40	140	0	0	0	0	120	80	1
Celatid	7	38	140	75	30	0	0	110	60	0
Cyberdisc	4	34	130	75	30	0	0	110	60	0
Sectopod	3	34	100	75	30	50	35	110	60	0

Damage Type	Value
Armour Piercing	0
Incendiary	1
High Explosive	2
Laser	3
Plasma	4
Stun	5
Melee	6
Acid Spit	7

Turret damage types for aliens and tanks follow the same damage types for normal weapons. With a little testing on my part, it was determined that the value of 6 was melee. Editing these values only changes the type of damage the weapon inflicts, not what the bolt looks like coming out of the turret. It is interesting to note that the Sectopod's damage type is 3 which corresponds to laser, not plasma as is often assumed.

Firing Accuracy Stats

Firing "Accuracy" is a little confusing, but hopefully this will clear up any confusion. The first type of accuracy is weapon firing accuracy. This is the accuracy of the weapon iteslf. Next is unit firing accuracy, which is how well (or how proficient) the unit can fire a weapon. These two accuracies are then multiplied together to get a "base chance to hit" (or BCTH). BCTH is the unmodified accuracy you see when clicking on a weapon.

Terrorist with integrated weapons have a firing accuracy which works in the same manner. The "turret" weapon accuracy is multiplied by the terrorists firing accuracy leading to a BCTH. These numbers are what the unit will see during a mission for firing accuracy.

Alien	Shot Type	Beg.	Exp.	Vet.	Gen.	Sup.
Celatid	Auto	DNA	DNA	DNA	DNA	DNA
	Snap	37%	79%	84%	88%	93%
	Aimed	55%	116%	123%	129%	136%
Sectopod	Auto	15%	31%	33%	35%	37%
	Snap	22%	47%	50%	52%	55%
	Aimed	33%	69%	73%	77%	81%
Cyberdisc	Auto	DNA	DNA	DNA	DNA	DNA
	Snap	22%	47%	50%	52%	55%
	Aimed	33%	69%	73%	77%	81%

Melee Stats

There are four aliens in the game which rely on melee (or Hand To Hand) as their primary attack method. It was determined that a single HTH attack costs a constant 15 TU no matter what the alien, their stats, or the skill level. It is therefore possible to construct a table showing how many attacks each alien could wage in a single round:

Alien	Damage	Beg.	Exp.	Vet.	Gen.	Sup.
Reaper	90	4	4	4	4	4
Chryssalid	110	7	7	7	8	8
Silacoid	70	2	2	2	2	3
Zombie	84	2	2	2	2	2

Accuracy of melee attacks is not guaranteed to be a successful event, even though the alien needs to be standing on a tile next to your unit. Calculating melee accuracy is very similar to firing accuracy determinations (see above), except that in melee accuracy, you multiply the melee accuracy stat by the units strength rating. The result is the infamous base chance to hit. Note that because both of these stats increase with respect to skill level, the BCTH jumps fairly fast. In fact, at Genius and Superhuman skill levels, the Chryssalid is more than 100% accurate leading to automatic success (zombification).

Alien	Beg.	Exp.	Vet.	Gen.	Sup.
Reaper	72%	75%	79%	84%	89%
Chryssalid	88%	92%	98%	103%	108%
Silacoid	56%	58%	61%	65%	69%
Zombie	67%	67%	67%	67%	67%

Psionic Stats

There are two alien races which possess psionic abilities: Ethereals and Sectoids. All Ethereals and the Sectoid Leaders and Commanders have this attribute. It was determined that a single psionic attack costs a constant 26 TU no matter what the alien, their stats, or the skill level. It is therefore possible to construct a table showing how many attacks each alien could wage in a single round:

Alien	Beg.	Exp.	Vet.	Gen.	Sup.
Sectoid Leader	2	2	2	2	2
Sectoid Commander	2	2	2	2	2
Ethereal Soldier	2	2	2	2	3
Ethereal Leader	2	2	2	2	3
Ethereal Commander	2	2	2	2	3

To generalize, each alien can wage two psionic attacks per round. Only Superhuman Ethereals can wage three.

Acknowledgments

A project of this size and magnitiude could never be completed without some help. I would like to extend my deepest thanks and gratitude to the following individuals:

NKF for his "lemon" psi stat viewer.
Bomb Bloke for his "dump" unitref viewer/logger.
Hatfarm for his excellent editors.
Stewart for providing the original 1.0 executable for testing.
MikeTheRed for for cracking the core stats from each executable version and invaluable technical assistance.
Seb76 for deciphering three unknowns in the alien stats (Loftemps Indexes and MCD Index).

Game Card

UFO Enemy Unknown

Developer:	Mythos Games
Publisher:	Microprose
Released:	1994

Databank

X-COM Series

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