What is an efficiency study? Efficiency in health care is studied by comparing two different treatments on the basis of results and costs.
Efficiency studies simply ask the question: which treatment is the most effective, and how much does it cost?
That way, researchers are constantly looking for the most efficient treatment thus keeping health care as effective and affordable as possible. ZonMw supports this kind of research through subsidies. But how do efficiency studies work? Researchers initially study whether a treatment is effective. 
Effective means that the treatment does what it has to do. For example: a bandage should stick to skin. This is studied by using a bandage on a group of people. If it sticks to the skin for a whole day, it can reasonably be said to be effective. 
Next, the effectivity is studied by checking if a different treatment works better than the current treatment. It’s also possible to check whether a treatment is better than doing nothing at all. Suppose a new bandage is developed with a special gauze for quicker wound healing. A study would test whether a wound heals faster when using the special bandage. To study this, two big groups of people with a wound are needed.
One group gets the standard bandage, while the other gets the new bandage. Both groups are subsequently studied to see how much time it takes for their wounds to heal. Then the costs of the new bandage are examined. These costs should weigh up against the benefits.
Suppose the new bandage is three times more expensive than the standard bandage. Then it would seem unwise to pay the extra costs if the healing process is sped up by just two minutes. If the process is sped up by two days the higher costs can suddenly seem reasonable. But what if the bandage causes a terrible itch? And patients do not want to use it because of that? That can be a reason to stop using the bandage.  If studies show that one treatment is more efficient than another there is scientific proof of the best treatment procedure. Non-treatment can also be the best option. This means that other treatments will be used less or sometimes stop being used at all. That way health care will be more efficient and everyone can get the care they need now, and in the future!