The most used indicators related to occupational safety are indicators that generally refer to accidents that have occurred, they are lagging indicators, because the measures that they offer can no longer avoid the accident that has already happened. This article presents a tool based on the use of leading indicators that, by contrasting them with certain lagging indicators, allows the predictive evaluation of the possibility of occurrence of work accidents in the construction sites in which it is applied. This paper explains the methodology followed for the design of the predictive tool and discusses it applicability. The obtained results lead to establish significant statistics correlations between some of the leading indicators formulated in the survey and accident data occurred in each case (lagging indicators), and therefore the predictive tool of work accidents in the construction works can be validated. The predictive capacity get 85.0% for minor accidents and 82.8% for major accidents. Keywords: crisis, accident rate, construction, accident