Candidates for the presidential election of the US collect donations in relation to their campaigns.

Candidates are sometimes compared based on the total amount of donations they received.

But what do the numbers actually mean to a candidate?

I see aspects of the campaign that are affected by the availability of money in a simple way. There are expensive technical resources that are expected to increase the rating of the candidate. For example air time in TV, number of print ads.

These seem to scale linearly: Double the money results in a doubled effect. Spending 1000 $ more increases the return by a known estimate.

With this, the candidates compete on a simple, brute force resource based competition. If that is all there is to campaign donations, it makes sense to compare candidates by total amount of donations received, because their probability to win are dependent on the amount in a simple way.

Apart from that, there are other aspects of received donations, and I would like to understand their relevance:

* The total amount of donations is correlated to popularity, and therefore, a high amount demonstrates high popularity to the public.
* Thee candidates compete on limited resources that are available only to one or few highest bidders. For example, there may be known best advertising agencies.
* Available cash allows for general flexibility. But is this relevant?
* The number of campaign events could be limited by available money, but I would assume it is typically by available candidate time.
* Donations could support providing transport and accommodation to large numbers of supporters to travel to campaign events - is that used?

Are some of these, or any other aspects of campaign donation totals relevant?