Thanks Doris. I'll find out more it. Thanks again.

To assess digital portfolios you could use an analitic rubric instead of a holistic rubric. Data resulting from this type of rubric is possible to be used for quantitative analysis. For qualitative analysis it might be better to use a holistic rubric +  data from an open question to the students.

I don´t know the Computer Programme MAXQDA mentioned by Doris Elster

Amparo

Laura, here is an article that might be helpful:

ABRAMI, Philip; BARRETT, Helen. Directions for Research and Development on Electronic Portfolios. Canadian Journal of Learning and Technology / La revue canadienne de l’apprentissage et de la technologie, [S.l.], Oct. 2005. ISSN 1499-6685. Available at: . 

Link to full text:

http://www.cjlt.ca/index.php/cjlt/article/view/92/86%26num%3B1

There is also a 2009 edited volume by Adamy and Milman, titled "Evaluating Electronic Portfolios in Teacher Education" that could have additional references. It's available on Amazon in paperback.

Joan Vandervelde from U Wisconsin-Stout also has an example of a rubric she developed posted at

https://www2.uwstout.edu/content/profdev/rubrics/eportfoliorubric.html  

with a link to additional resources on authentic assessment.

Hope that's useful.

http://www.cjlt.ca/index.php/cjlt/article/view/92/86%26num%3B1

https://www2.uwstout.edu/content/profdev/rubrics/eportfoliorubric.html