Computer system for estimating operational risk

A method of calculating a risk caused by a mistake in operation in a computer system having a plurality of first computers each operated by an operator and a second computer coupled via a network to the plurality of first computers,

• the method comprising:
• executing, by each of the plurality of first computers, at least one software:
• obtaining, by each of the plurality of first computers, operation information by the operator with respect to the at least one software to be executed;
• receiving, by each of the plurality of first computers, an input of information from the operator;
• displaying, by each of the plurality of first computers, a confirm window for the operator to check whether the received input information is correct or not;
• calculating, by each of the plurality of first computers, operation time period about the displayed confirm window based on the acquired operation information;
• sending, by each of the plurality of first computers, the calculated operation time period about the confirm window to the second computer;
• receiving, by the second computer, the operation time period about the confirm window;
• and
• calculating, by the second computer, the number of operations of which the received operation time period about the confirm window is shorter than a first threshold value.