The overconfidence effect occurs when our subjective confidence in our own capability is greater that the actual or objective performance.
This means a person is so confident in a way that they measure their capabilities beyond what they can actual do in reality. A person doesn't take into account the effect of reality in their actions. A person doesn't consider some other facts or aspects that may come their way to actual create a setback in what they are planning. This is seen in planning fallacy when a person overestimate the times it would take them to finish a task , they do this by not considering that in everything we do they may be some delays or stumbling blocks we may have to face and deal with that may even affect our decision or planning.
