Naam Sankirtan is scientifically based on the theory of sound therapy. Every word originates from sound and each sound has its echo. So devotees repeatedly recite Lord's name (naam) so that its echo begins to be heard from inside (ajpa jap). This has been considered as the most effective means to experience union with God in Kalyuga. 
Sankirtan implies a group session of devotional singing. An apt harmony between swar (sound) and bhaav (spirit) enables us to get easily absorbed in Lord because music has the capacity to make our mind thoughtless. The 'Divine sound vibrations' render the whole ambience pure and thus provide a blissful experience to the attendees with a long lasting impact. If we are moved by any of the words/expression, the internal echo continues to repeat it even after the external session ends. Such a blessed state, of turning inwards, is a personal attempt as well as accomplishment. So for the ardent seekers, who feel painful longing for God, chanting brings profound results in a little time.