Research

Research is used to unlock technologies.

Research slots

Technology is unlocked by assigning a research slot to it for the required number of days.

The base number of research slots depends on the country:

• USA, democratic Germany: 4 slots, plus 2 additional possible via national focus. (Democratic Germany requires Waking the Tiger).
• Non-democratic Germany, Italy, Japan, United Kingdom: 4 slots, plus 1 additional possible via national focus.
• France, Soviet Union, most other countries in Europe, plus Canada: 3 slots, plus 2 additional possible via national focus (in Canada's case, the last 1 requires independence).
• Other countries outside of Europe as well as Luxembourg, Bulgaria and Albania: 2 slots, plus 3 additional possible via national focus (for British subjects, the final 2 also require independence).
• New Zealand: 2 slots, plus 4 additional possible via national focus. (Requires Together for Victory).

For most countries, unlocking the final research slot requires having a substantial number of factories (usually 50+). The Commonwealth countries must (with Together for Victory) additionally become fully independent to maximize their available research slots.

Each research slot can store 30 days of research while unused.

Research time

Each technology has a base time cost:

Cost (days)	Techs
50	Armor Submodels
100	Artillery (II) & Upgrades (II,III,IV); Anti-Air Artillery (II,III) & Upgrades; Rocket Artillery (II) & Upgrades; Anti-Tank Artillery (II,III) & Upgrades Support Equipment; Carrier Airplanes; Electronic Mechanical Engineering; Encryption
150	Infantry Weapons (I) & Upgrades (I,III); Support & Anti-Tank Weapons; Motorized Rocket Artillery; Marines (II), Mountain Infantry (II), Paratroopers (II) Support Companies (II,III,IV); Artillery (I) & Upgrades (I); Anti-Air Artillery (I); Anti-Tank Artillery (I) Ships (I); Transports (I); 1st Land Doctrine; 1st Air Doctrine Radio; Radio Detection; Decimetric Radar (I); Decryption; Experimental Rockets; Rocket Engines (II,III) Machine Tools (I,II); Equipment Conversion; Oil Processing; Rubber Processing
200	Infantry Weapons (II,III) & Upgrade (II); Night Vision (II); Motorized & Mechanized (I,II); Marines (I,III), Mountain Infantry (I,III), Paratroopers (I,III); Special Forces Programs Support Companies (I); Artillery (III); Rocket Artillery (I); Great War Tank, Light, Medium & Heavy (I) Armor Ships (II,III,IV); Transports (II,III); Naval Doctrines Airplanes; Air Doctrines (not 1st) Decimetric Radar(II); Rocket Engines(I); Jet Engines Machine Tools(III); Production Line (I); Industry; Construction; Excavation
250	Night Vision (I); Modern, Super Heavy & Heavy (II,III) Armor; Centimetric Radar; Computing; Production Line (II)
300	Mechanized (III); Land doctrines (not 1st); Synthetic Oil Experiments
500	Nuclear technology

This is then modified by general and specific research time modifiers:

General modifiers

These apply to all techs.

Difficulty

The player can get a research time bonus or penalty depending on the game difficulty setting as follows:

• Civilian -10% bonus
• Recruit -5% bonus
• Regular no bonus or penalty
• Veteran +10% penalty
• Elite +20% penalty

Trade law

Main article: Ideas#Trade_laws

Trade laws can also reduce research time. The more open the trade the higher the reduction as can be seen below.

Law	Resources to Market	Dockyard/ Factory Output	Construction Speed	Research Time	Prerequisites
Free Trade	80%	+15%	+15%	−10%	–
Export Focus	50%	+10%	+10%	−5%	–
Limited Exports	25%	+5%	+5%	−1%	One of the following must be true: All of the following must be true: At war. Current ruling party is Democratic. Any enemy country has more than 20% of this country's total number of factories. All of the following must be true: Current ruling party is not Democratic. has economy law: Partial Mobilization, War Economy or Total Mobilization.
Closed Economy	0%	–	–	–	At war Current ruling party is Fascist or Communist. has economy law: War Economy or Total Mobilization. If this country is the Soviet Union, it should not have the ‘Molotov-Ribbentrop Pact’.

Technologies that reduce research time

Technology	Year	Base Time to Research	Research Time
Electronic Mechanical Engineering	1936	100	-2%
Mechanical Computing	1936	250	-3%
Computing Machine	1938	250	-3%
Improved Computing Machine	1940	250	-5%
Atomic Research	1940	500	-2%
Advanced Computing Machine	1942	250	-5%

Bonuses from these technologies are applied to other research under way at the time the technology is completed, as well as research begun after the bonus technology has completed.

Specific modifiers

These apply to specific techs. Note that the sum of these stacks multiplicatively with general modifiers. Modifiers are computed when a tech starts researching.

• Ahead of time penalty: +200% per year.
• Research bonuses: These are generally gained via national focus. Usually a -50% modifier to a tech or a -100% ahead of time penalty, applied when next eligible research project starts or restarts.
• Research and Production: Under Political, various designers, concerns and theorists can provide -10% or -15% bonus to research.Note at what point in the research project these modifiers are applied.

Note that ahead of time research length does not scale linearly with ahead of time itself because the penalty is reduced over time. The number of days required for ahead of time research (assuming the research is completed before the penalty is removed) is as follows.

$t=365\times ({\text{number of years ahead at start}}+{\frac {1}{2}})\times \left(1-e^{-{\frac {2}{365}}\times {\text{research cost in days}}\times (1+{\text{research bonus}})}\right)$

The research bonuses through National Focus and other smaller research modifiers both apply subtractively to research cost. For example, a minor nation with -5% research bonus from Export Focus and -50% from National Focus on a 200-day armor model has an effective research cost of $200\times (1-5\%-50\%)=90$ days.

Technologies

Technologies allow countries to unlock production of new units such as mechanized infantry, paratroopers, tanks and all kinds of airplanes; new equipment, from infantry weapons to carrier air groups and specialized armored units; as well as defensive and productive structures.

On the other hand, most technologies serve to improve the efficiency of current units. This can be achieved through a number of ways, such as improving the damage inflicted by the unit, its ability to penetrate the armor of armored units, its defensiveness and organization or simply its ability to detect enemy units.

It is possible to research improvements of already researched technologies. There could be small buttons on technology (e.g. possibility to operate from carriers for airframe). These improvements have to be researched separately.

Land

• Infantry technology: Technologies that improve infantry weapons and equipment, unlock or improve motorized and mechanized units as well as special forces (marines, mountaineers and paratroopers).
• Artillery technology: Technologies that unlock and improve all types of artillery, including anti-tank, anti-air and rocket artillery.
• Support Companies technology: Technologies that unlock and improve all types of support battalions: Engineers, Reconnaissance, Military Police, Maintenance, Field Hospital, Logistics and Signal companies.
• Armor technology: Technologies that unlock all types and models of tanks, from light to super heavy chassis, as well as their variants: tank destroyer, self-propelled artillery and self-propelled anti-air.
• Land doctrine: Unlocks one of the four land doctrine trees: mobile warfare, superior firepower, grand battleplan and mass assault.

Naval

• Naval technology: Technologies that unlocks or improve all kinds of ship units: destroyer, cruisers, battleship, carrier, submarine or improve transports for naval invasions.
• Naval doctrine: Unlocks one of the three naval doctrine trees: fleet in being, trade interdiction and base strike.

Air

• Air technology: Technologies that unlock or improve all types of airframes: light, medium or heavy, as well as their jet propulsion versions.
• Air doctrine: Unlocks one of the three air doctrine trees: strategic destruction, battlefield support and operational integrity.

Industry

• Engineering technology: Groups all technologies related to electronic engineering (computers, radios, cryptography), rockets and atomic research.
• Industry technology: Groups all technologies that improve production efficiency and volume of all factories, resources excavation and unlocks synthetic refineries.

Doctrines

All doctrines listed above serve to improve units in a specific role by providing them one or multiple bonuses once the doctrine has been researched. Some of these bonuses can be obtained through more than one doctrine, but at different depth of the doctrine tree and most bonuses are unique to a specific doctrine.

It's also necessary for all players to make a choice when researching doctrines, as opposed to all other technologies (with the exception of Industry) that can be entirely researched. Only one doctrine can be researched out of three or four options, depending on the doctrine type (land, naval or air).

It's possible to change doctrine throughout the game, but all bonuses from the old doctrine are lost, as if completely abandoned, when starting research of a different doctrine tree.

Technology sharing

Some countries may share their technological progress with other members of the sharing group they are part of. This means that they will receive a reduced research cost for technologies already researched by other members and vice versa. Sharing groups are not necessarily limited to faction. If more members have researched a technology, the the discount will be greater.

Certain sharing groups may be restricted to specific technological areas, such as electronics or radar, where others, for instance the British commonwealth, are universal in this respect. Commonwealth technology sharing is automatic from the start of the game. Others can access specific sharing arrangements by national focus, or by turning on and maintaining a continuous focus if that is available. Cooperation and coordination in research can be very effective in multiplayer games.

The sharing bonus may be reduced for puppets depending on their autonomy level.