Some of the most important decisions in SEO are based on search volume data. We use it to compare keywords, to guide our content strategy, and to make traffic projections. We may even use it to predict conversions and revenue. And yet, it is one of the least reliable pieces of data to exist in SEO.
If you ever tried comparing search volume data across keyword tools, you probably know that the numbers are usually very different. Like, surprisingly different. For example, here is what happens when I research the same keyword across some of the most popular SEO tools: