I wouldn't say it's specifically because fixed costs are harder to control.
Rather, in all aspects of casing you need to understand the nature of the beast better! Segmenting and categorizing things helps you do this. Essentially, it helps you understand where to go next.
My Advice For Cost Cutting
In general, for determining cost issues, you need to break down the problem into a tree/root-cause analysis and ask the highest level (but specific) questions first! In this way, you essentially move down the tree.
How do you identify where to look? Well, you need to look into whichever of the following 5 make the most sense based on where you are:
- What's the biggest? (i.e. largest piece of the pie...most likely to change the end result)
- What's changing the most? (I.e. could be driving the most and most likely to be fixable)
- What's the easiest to answer/eliminate? (i.e. quick win. Yes/No type of question that eliminates a lot of other things)
- What's the most different? (differences between companies, business units, products, geographies etc....difference = oopportunity)
- What's the most likely? (self-explanatory)
For more background on analyzing costs, look here: