Job crafting means actively altering one's job to better suit one's skills and interests. This type of proactive behavior leads to higher levels of work engagement and to better job performance, according to a recent longitudinal study authored by researchers from the Netherlands. The results further showed that the effects are more pronounced regarding performance in core tasks than for more discretionary performance (e.g., providing social support at work).
Tims, M., Bakker, A. B., & Derks, D. (2015). Job crafting and job performance: A longitudinal study. European Journal of Work and Organizational Psychology, 24(6), 914-928.