D e s pit e s ev e ral at t e m pt s t o prov ide a de f ini t e pat t e rn re g arding t he e f f e ct s of pe rs onalit y t rait s o n pe rf orm a nc e in hig h e r e du c at ion, t he de bat e ov e r t he nat u re of t he re lat io ns hip is f ar f rom be i ng c onc lu s iv e . T he us e of dif f e re nt s u bje ct pools and s am pl e s ize s , as we ll as the u s e of ide nt if ic at ion s t rat e g ies t hat e it he r do not ade q u at e ly ac c ou nt for s e le c t ion bias o r are u nable t o e s t ablis h c au s alit y be tw e e n m e as u re s of ac ade m ic pe rf orm anc e and no nc og nit iv e s k ills , are pos s ible s ou rce s of het e rog e ne it y . T his pape r inv e s t ig at es t he im pac t of t he B ig F iv e t rait s , as m e asu re d be f ore t he be g inni ng of t he ac ade m ic y e ar, on t he g rade p oint av e rag e ac hie v e d in t he f irs t y e ar af te r t he e nrolm e nt , t ak ing adv ant ag e of a u niq u e and larg e dat as e t f rom a c oh ort of It a li an s t u de nt s in all u nde rg radu at e pr og ram s c ont aini ng de t aile d inf orm at io n on s t u de nt and pare nt al c harac t e ris t ic s . Re ly ing on a robu s t s t rat e g y t o c re dibly s at is f y t he c ondit iona l inde pe nde nc e as s u m pt ion, w e f ind t hat hig he r le v e ls of c ons c ie nt iou s ne ss and ope nne s s t o e xpe rie nc e pos it iv e ly af f e c t s tu de nt s c ore .