It is recommended to open the links in the same window instead of opening it in a new window (attribute target=”_blank”) when a link is clicked. This behaviour gives your site visitors/users more control while opening the link, instead of the link opening everytime in a new window even though the user don’t wish to do so. Let the user decide what he/she wants to do. If user wants to browse the page in same window allow him to do so; if user wants to view the page in new window, user can always do that on its own by right clicking the link and open in new window or the control key + click command can do the job.
Always allow the users what they wish to do, and not what you want them to do.