Each hirable NPC has 7 skills and each skill has 5 levels of competency (the more stars, the better). Numbers of stars are somewhat randomly generated in that I don't think it is possible to get NPCs with really low numbers of stars any more. <Clarification: this may apply to hired NPCs only; 'free' NPCs given when buying or given plot ships may still have very low skills - Snafu>
Only the skills marked in bold font are relevant to the performance of the NPC in question (their Primary Skills). In most cases, each NPC will have three Primary Skills, but Engineers and some Specialists only have one. Marine Officers are unique in that they have a skill that improves with use: "Boarding Experience".
For all NPC types where we know the relative significance of their primary skills (see below), they have been listed in descending order of significance in-game. So for those NPC that we don't know the relative significances of their primary skills (e.g. Managers and Specialists) it is reasonable to assume that they may be in descending order, or of at least equal weighting. For the NPCs with 3 primary skills other than MOs, the average significance of a primary skill is 3.4 and, going down, their average weightings are 44%, 33%, 23%. Those percentages are roughly equivalent to ratios of 4.5:3.5:2.5.
We don't know the weightings for Mangers or Specialists. If wishing to compare Managers to each other, using that rough ratio above may be better than nothing. The same could be done with Specialists although perhaps they are more likely to have top-heavy weightings like Marine Officers.
In Rebirth 3.00, Virtual Seminars were introduced to the game, which allow us to add a star to a Primary Skill of our hired NPC. They are only currently available via Smalltalk from other NPCs and this feature is described in more detail in the official guide to 3.00 here and on this wiki here <edit: they may be obtainable as mission rewards too; needs checking - Snafu>. Virtual Seminars cannot be used to increase a Marine Officer's Boarding Experience, but since Virtual Seminars take some effort to acquire I would suggest that would be a waste anyway.
Info on exactly how the skill values are are used is sketchy but CBJ has revealed a few titbits:
Further info on Marine Officers from w.evans:
| NPC | Skills + (relative significance) | Effect | Description | Hire Fee |
|---|---|---|---|---|
| Skunk NPCs | ||||
| Engineer | Engineering (1) | Repairs damaged equipment (e.g. weapons). Doesn't repair Skunk's hull (only done by Engineers on stations) | 13'000 39'000 | |
| Marine Officer | Boarding (15) Leadership (3) Morale (2) | Affects boarding strength multiplier | 19'000 57'000 | |
| NPCs on Player-owned ships | ||||
| Engineer | Engineering (1) | 0* - repairs to 60% max hull 4* - repairs to 84% max hull | Repairs damaged surface elements and hull. They also do his job on NPC-owned stations but Player-owned stations cannot employ Engineers and so instead must pay Architects to do these tasks... Maximum repaired hull percentage: | 13'000 |
| Captain | Leadership (4) Navigation (3.5) Morale (2.5) | Captains control capital ships (AKA Large and Extra Large ships). This includes when following trading and combat orders. | 27'000 81'000 | |
| Defence Officer (AKA a DO) | Leadership (5.5) Combat (3.5) Morale (2) | Controls surface element weapons on capital ships in accordance with their orderstate and their Capain's orders. When set to Attack, any hostile target in range will be fired upon. When set to Defend, hostile targets will only be shot if they attack the ship or if the DO's Captain is running a combat-related order. | 58'000 174'000 | |
| Architect | Management (3.5) Engineering (3.5) Navigation (3) | These NPCs can only work on Construction Vessels and they are responsible for building selected stations, upgrading them with missing surface elements or additional production expansion options, equipping drones and initiating station repairs. | 36'000 108'000 | |
| Pilot | Navigation (5) Combat (3) Morale (2) | Pilots control Small and Medium ships. In combat with capitals, those ships typically attack surface elements (e.g. weak points that may be shooting back at them) rather than ship hulls. fight.attack.object.fighter.xml: | 11'000 | |
| NPCs on Player-owned stations | ||||
| Manager | Leadership Management Navigation | These NPCs work on stations and they're the equivalent of Pilots and Captains on ships. Managers look after creating Buy and Sell orders for their station, are required before ships can be assigned to work for stations, and supply a list of required wares to Captain's of assigned ships, who then decide what to buy. | 48'000 144'000 | |
| Defence Officer | as DO above | |||
| Specialists | ||||
| Boosts production up to 10% depending on cumulative skill | ||||
| Agricultural Engineer specialistagriculture | Engineering Science Leadership | Meat, Plankton, Soy Beans, Spaceweed, Spices, Wheat | 122'000 366'000 | |
| Cell Specialist specialistpowerstorage | Engineering | Antimatter Cells, Energy Cells, Fuel Cells, Ion Cells, Plasma Cells | 168'000 504'000 | |
| Food Technologist specialistfood | Engineering Science Management | BoFu, Food Rations, Spacefuel | 157'000 471'000 | |
| Chemical Specialist specialistchemical | Engineering Science Management | Bio-Electric Neuron Gel, Chemical Compounds | 185'000 555'000 | |
| Precision Assembler specialistprecision | Engineering | Bio-Optic Wiring, Microchips, Plasma Pumps, Quantum Tubes | 195'000 585'000 | |
| Weapons Technologist specialistweapons | Engineering Combat | All Missiles, EM-Spectrometer, Scanning Array, Warhead Components | 220'000 660'000 | |
| Pharmaceutical Agent specialistpharmaceuticals | Engineering Science Leadership | Medical Supplies, Narcotics | 147'000 | |
| Metallurgical Engineer specialistmetals | Engineering Science | Refined Metals, Reinforced Metal Plating, Silicon Wafers, Teladianium | 145'000 435'000 | |
| Geophysicist specialistgeophysics | Science Engineering Navigation | Cut Crystals, Nividium Cubes | 128'000 | |
| Surface Technician specialistsurfacesystems | Engineering | All Turrets, Force Field Projector | 232'000 696'000 | |
| Power Specialist specialistpowersupply | Engineering | Fusion Reactors, Podkletnov Generators, Plasma Flow Regulators | 210'000 630'000 | |
| Hydro Specialist specialistaquatics | Science Engineering Navigation | Water | 115'000 345'000 | |
4.0 Beta 4 added parameters section regarding AI flight behaviour: low piloting skill causes penalities with steering and acceleration (up to 0.5), also it adds some delay between actions.