The idea for this MOD is simple and it goes something like this...
You have a knob/dial in the MOD selection screen which you can adjust to the level of your choice, and then if your accuracy falls below the level you have chosen with the MOD, you fail the beatmap. Since everyone has different accuracy skills, having an adjustable setting would mean that each person could set it close to the level that they can cope with. And then over a period of time, the person could adjust the setting to a higher level when they improve their accuracy.
You have a knob/dial in the MOD selection screen which you can adjust to the level of your choice, and then if your accuracy falls below the level you have chosen with the MOD, you fail the beatmap. Since everyone has different accuracy skills, having an adjustable setting would mean that each person could set it close to the level that they can cope with. And then over a period of time, the person could adjust the setting to a higher level when they improve their accuracy.