i. Basic cost standard represents constant standards that are unchanged over a long period. The main advantage is that a base is provided for comparison with actual cost through a period of years with the same standard, allowing efficiency trends to be established over time. However, when changes occur in production methods, price levels, or other relevant factors, basic standards become less useful as they do not represent current targets.

ii. Ideal standards represent perfect performance. Ideal standards are the minimum cost possible under the most efficient operating conditions. These standards are unlikely to be used because they may negatively impact employee performance.

iii. Currently attainable standards represent costs that should be incurred under efficient operating conditions. They are difficult but not impossible to achieve, with allowances made for normal spoilage, machine breakdowns, and idle cost.