It is known that the calculated values of log<i>ft</i> and the half-life of beta decay are less than the measured values when a single-particle approach is used to calculate these quantities. In this article, we discuss the importance of taking into account the spectroscopic factor in the calculation of the half-life and log<i>ft </i>beta decay of nuclei containing one nucleon in the outer-most shell. We also emphasize on the dominant role of the asymptotic normalization coefficient that takes into account the many-particle effect and allows us to obtain the spectroscopic factor necessary to describe the reaction <sup>13</sup>N → <sup>13</sup>C+β<sup>+</sup>+ν<sub>e</sub>. We find the asymptotic normalization coefficients using the experimental data of the elastic scattering phase-shift of proton and neutron on <sup>12</sup>C. Using overlap functions, instead of single-particle functions, we obtain a better comparison with the experimental data. The overlap function is represented as the product of single-particle function and the root of the corresponding spectroscopic factor.