In the 1960s, expert systems were proposed as the solution to the scarcity of human expertise. Experts were expensive or hard to find, and technology seemed ready to replace them. The only task for knowledge engineers was to acquire expert problem-solving rules, which could then readily be implemented as production rules in an expert system. Advantages were also expected in the quality of the conclusions: Computer systems did not get tired or bored, would not be distracted by irrelevant details, and would always perform consistently and correctly.