Some essays can have lots of technical data in them, but they are still an essay. Why? The difference between an essay and a technical report is actually rather difficult to define: as with most things, there is not a definitive line we can draw between the two. Here are some basic ideas about the differences:
Author's stance.
In an essay, the scribe takes an argumentative stance often stated as a thesis (a specific opinion). In essays, authors use arguments to make their point. In a technical report, the scribe has a major issue, but it is not ...