evidence for pairing effectiveness

When I run a cyber-dojo I always ask the participants to work in pairs, two people per computer. I've been doing some research on pairing and I've come across a book called Visible Learning by John Hattie. It's a synthesis of over 800 experiments and papers relating to achievement in schools. On page 225 there is a section called The use of computers is more effective when peer learning is optimized. It reads, and I quote...

• Lou, Abrami, and d'Apollonia (2001) reported higher effects for pairs than individuals or more than two in a group.
• Liao (2007) also found greater effects for small groups (d=0.96) than individuals (d=0.56) or larger groups (d=0.39).
• Gordon (1991) found effects were larger for learning in pairs (d=0.54) compared to alone (d=0.25).
• Kuchler (1998) reported d=0.69 for pairs and d=0.29 for individuals.
• Lou, Abrami, and d'Apollonia (2001) reported that students learning in pairs had a higher frequency of positive peer interactions (d=0.33), higher frequency of using appropriate learning or task strategies (d=0.50), persevered more on tasks (d=0.48), and more students succeeded (d=0.28) than those learning individually when using computers.

What do the numbers mean? Quoting from the front of the book...

An effect size of d=1.0 indicates an increase of one standard deviation on the outcome - in this case the outcome is improving school achievement. A one standard deviation increase is typically associated with advancing children's achievement by two to three years, improving the rate of learning by 50%, or a correlation between some variable and acheivement of approximately r=0.50. When implementing a new program, an effect size of 1.0 would mean that, on average, students receiving the treatement would exceed 84% of the students not receiving that treatment.

Of course, things are rarely absolutely black and white, but these are impressive numbers.

• Lou, Y., Abrami, P.C., & Apollonia, S. (2001). Small group and individual learning with technology: A meta-analysis. Review of Educational Research, 71(3), 449-521
• Liao, Y.K.C. (2007). Effects of computer-assisted instruction on students' achievement in Taiwan: A meta-analysis. Computers and Education, 48(2), 216-233.
• Gordon, M.B. (1991). A quantitative analysis of the relationship between computer graphics and mathematics achievement and problem-solving. Unpublished Ed.D., University of Cincinnati, OH.
• Kuchler, J.M. (1998). The effectiveness of using computers to teach secondary school (grades 6-12) mathematics: A meta-analysis. Unpublished Ed.D., University of Massachusetts Lowell, MA.