More systematic studies are needed in order to test the benefits of DDL

In different ways, the use of concordancers, concordance lines and language corpora promoted the use of information technologies and active search strategies, which was perceived as a valuable asset. Recently, Johansson (2009:41) claimed that more systematic studies are needed in order to test the benefits of DDL and that it is necessary to discuss “students’ problems with corpus investigation” so that specialists can “suggest how [learners] could be better equipped to be corpus researchers”. 

From Pérez-Paredes, P.Sánchez-Tornel, M. and Alcaraz Calero, J.M. Learners’ search patterns during corpus-based focus-on-form activities. A study on hands-on concordancing. International Journal of Corpus Linguistics 17:4. 2012. iii, 150 pp. (pp. 482–515)

The difficulty of conducting empirical studies

“Empirical studies are extremely difficult to conduct in applied linguistics, as indeed in any other area of social sciences or the humanities, given the enormous number of different factors which can impact on any given study” (p.264).

Boulton, A. (2012). Corpus consultation for ESP. In  Boulton, A., Carter-Thomas, S. and Rowley-Jolivet, E. (eds.). 2012. Corpus-Informed Research and Learning in ESP. Issues and applications. Studies in Corpus Linguistics, 52. Amsterdam: John Benjamins: pp. 261-292.