the highest and lowest, it can be largely unreliable as often firms can have high variances in production levels and this method would not be able to capture the average activity levels. There are more accurate methods such as the least-squares regression, although this is much more complex to use.

Another major drawback of the high-low method is that only one variable is taken into account. For example, if the variable cost is measured by time (e.g. per hour), but the firm wants to produce at