Must “firstly,… secondly, …” or “first,… second, …” always follow “There are X number of reasons”?

Question

I have read hundreds of posts where people debated over the use of "firstly, secondly, ..." and "first, second, ..." My understanding is it comes down to style and neither is wrong. However, I can't seem to find the answer I am looking for.

I am writing an academic paper. My question is this: Regardless of which form I choose, does "firstly, secondly, ..." or "first, second, ..." have to be preceded by "There are X number of reasons for this."

For example, must the sentence structure be like this: There are three reasons for why that is the case. First,... Second,... And finally/more importantly,...

In my case this is what I have:

Paragraph 1: [Explained how a program works, and the stated rationale for using unemployment rate as an indicator of employment prospect.]

Paragraph 2: But the regional unemployment rate, as many often argue, is not an appropriate indicator of an individual’s employment prospects (XX 2011; YY 2009). First, the regional unemployment rates are seasonally adjusted 3-month-moving averages. This means that the adjustment of the entrance requirements (i.e., the VERs) considerably lags actual conditions in the regional labour markets (YY 2009). Second, as XX (2011, 1) points out, the regional unemployment... And most importantly....

I don't want to say there are X number of reasons, cause there might be more. Also, the part in bold is a fact, which creates a problem, but the fact is not the problem. I just want to use "first, second, ..." for pointing out how those points are different.

Answer 1

If your intention to enumerate the reasons is implicitly clear, there is no requirement to do so explicitly. Indeed, by writing “firstly”, your second paragraph is clearly declaring your intention to enumerate.

Be careful, however, that there isn't too much text between the first and the last reason, or the reader won't know when you have finished the list. This is the main reason to declare in advance how many reasons you will give: it avoids confusion and frustration in the reader.

Note that declaring that there are X reasons is by itself a claim that there are exactly X reasons, that is, that there aren't any more. If you don't mean to do that, then you can say, for example, “We will highlight/we can identify X of the many reasons”.