Law firms employ personal researchers to get possible witnesses and job interview them because it all is cheaper for the customer to pay out the detective than it all is to pay out the attorney. Mengenai latar belakang pengguanaan wawancara sebagai metode pengumpulan information pada suatu penelitian, pendapat Allport ( dalam Hadi, 1992) berikut perlu dipertimbangkan: If we prefer to learn how persons look, what their experience and what they remember, what their emotions and factors are like, and the good causes for acting as they carry out – why not ask them?