"has evidenced" is correct and usable in written English.
You can use it when talking about something that has been presented as evidence. For example: "This report has evidenced a strong relationship between income level and educational attainment."
George Bush has evidenced serious weaknesses.
Our government has evidenced what many will consider moral bankruptcy".
A case study conducted in the legislative domain has evidenced the advantages of our system.
In the last few decades, pressure swing adsorption (PSA) has evidenced substantial growth in terms of size, versatility and complexity.
Degradation product analysis has evidenced the breaking of Mdda chains that are largely responsible for the toxicity of microcystins.
The past decade has evidenced a threefold increase in the amount of software and tools in the online repositories.
More than once in the last decade such sampling has evidenced the catastrophic decline of populations within the five years, leaving fewer options for adapting conservation strategies.
Virtually every scholar who has considered the matter has evidenced a certain amount of originality in his view of the interrelationships among religious forms.
A recent international exercise has evidenced that the current approaches overestimate drastically the strength of composites under compressive loadings, even for quasi-isotropic laminates.
The direct validation has evidenced an excellent agreement with correlations up to 0.98 in 2008 and 0.92 in 2011 in some sites.
The creation of the European Higher Education Area (EHEA) has evidenced the need for the development of language policies at universities.
