The importance in the papers' impact of the number of pages and of co-authors - an empirical estimation with data from top ranking economic journals

On a regular basis the scientific output of academic people has to be evaluated, e.g. to decide tenure. A very important item in this evaluation is the published papers’ quality that tends to be approximated by its impact in the literature. As the measure of this impact requires a long-term analysis, thus it is used as its estimator the journal average impact where each paper is published. But some papers have a single author while others have several and some papers have one or two pages while others have more than fifty. In this work I validate the conjecture that these two variables have a significant and positive effect in papers’ future impact, i.e. in papers quality. Nonetheless, I quantify that this two variables jointly considered merely explain 2.8% of papers’ impact variability.