It’s a passive voice problem.
In this sentence:
The factors which consistently affect accuracy are those which directly or indirectly (as in the handling of continuous attributes) allow a greater number and variety of potential trees to be explored.
The trick is to simplify it down to parts.
It seems that the following are implied:
We are building a method.
We want the method to produce accurate results.
We will discuss which factors improve accuracy and which don’t.
So let’s simplify:
The factors which consistently affect accuracy are those which directly or indirectly (as in the handling of continuous attributes) allow a greater number of potential trees to be explored.
We have:
The factors which affect accuracy are those which allow a number of trees to be explored.
- Notice that “of potential trees” is a prepositional phrase. You can often remove prepositional phrases from sentences without affecting their grammar. In this case, of is modifying “a number”.
- “To be explored” is related to the verb allow.
It’s tempting to simplify by getting rid of “a number“, and keep “trees“. For the purposes of the grammar, though, “trees” is in a prepositional phrase. Prepositional phrases are almost always self-contained and can be removed from the sentence without disturbing the grammar.
So, simplify again:
We have:
The factors which affect accuracy are those which allow a number (of trees) to be explored.
The key is:
- allow (a number) (to be explored)
This is passive voice, which usually drops of the subject of verbs.
The subject is implied:
- allow (a number) (to be explored) (by the method)
Or:
- allow the method to explore a number.
So a final simplification:
** The good factors allow the method to do more, and go faster.**.
