Spectral analysis is nowadays a widely used tool to investigate the evolution of galaxies. Assessing the reliability of this approach is crucia, motivating a through analysis. In this poster, a comparative study between two widely tools, FADO and STECKMAP, is performed, focusing on the discrepancies between the different approaches. Both codes use different methods to extract the best fit, allowing the possibility to disentangle possible biases introduced in the analysis. Our analysis showed that where nebular emission is not negligible, the results obtained with methods taking into account such a component are more reliable, and this can be very important when moving at higher redshift, where stellar populations are younger. In particular, this is true for starburst systems, where a huge amount of stars are forming almost at the same epoch. This is an important aspect to take into account the future survey, as JWST for example, which will provide the community with medium resolution spectra of galaxies at redshift 3-4 and even higher.