When an error is difficult to categorise

It might help you to understand some of the terms I use in my feedback if you consider one or two examples which I find difficult to categorise:

1: Is the problem here related to SENTENCE STRUCTURE or PUNCTUATION?

The first two authors teach at Essex Business school, University of Essex, UK, while the third works for Pantheon Ventures–Russell Private Equity, They have written several articles about the analysis of UK IPO underpricing and venture capitalists.

We could certainly classify this as a SENTENCE STRUCTURE problem.  Some teachers and writers will call this a RUN-ON SENTENCE.  To fix it, though, we just need to pay attention to PUNCTUATION:

The first two authors teach at Essex Business school, University of Essex, UK, while the third works for Pantheon Ventures–Russell Private Equity; they have written several articles about the analysis of UK IPO underpricing and venture capitalists.

Where possible, I like to use the term that will enable the easiest correction of the problem, so in this case I’d probably bring the student’s attention to PUNCTUATION.

2: Is the problem here WORD CLASS or PATTERN GRAMMAR?

They have written several articles about analysis  UK IPO underpricing and venture capitalists.

Again, it could be either of these issues.  With attention to WORD CLASS, our correction becomes:

They have written several articles about analysing UK IPO underpricing and venture capitalists.

PATTERN GRAMMAR might lead us to:

They have written several articles about the analysis of UK IPO underpricing and venture capitalists.

3: Is this an example of a WORD CLASS or COLLOCATION problem?

an abundant of knowledge

What’s more important?  The fact that “abundant” is an adjective and so should be corrected to the noun “abundance” or the fact that “an abundance of knowledge” is a strange combination of nouns that a reader might not understand.  In this case, I think we can arrive at a better correction via attention to COLLOCATION (I would suggest “considerable knowledge”, an option listed in the Oxford Collocations Dictionary).

4: Are these examples of COLLOCATION or PATTERN GRAMMAR problems?

The results describe that…

The results present that…

Perhaps it's easiest just to say "both".  Results don't "describe" or "present" anything, so the writer should find another combination.  At the same time, DESCRIBE and PRESENT should be followed by a NOUN PHRASE, not THAT and then a Subject + Verb.  The whole phrase needs to be rewritten!