Before revision: In the construction industry, the 1:5:200 rule (or 1:5:200 ratio) is a rule of thumb that states that the initial construction costs of a building, the operating costs over 20 years, and the business staffing costs over 20 years could be expressed by the ratio 1:5:200.
After revision: In the construction industry, the 1:5:50 rule (or 1:5:200 ratio) is a rule of thumb that states that the initial construction costs of a building, the operating costs over 20 years, and the business staffing costs over 20 years could be expressed by the ratio 1:5:200.