Group-Based Management Consulting for Auto-Parts SMEs — Colombia's CNP Productivity Trial

Between 2013 and 2017, Colombia's Centro Nacional de Productividad (CNP) worked with World Bank researchers to run a randomised controlled trial testing two ways of delivering management consulting to second-tier auto-parts suppliers across Antioquia, Cundinamarca, Valle del Cauca and the Eje Cafetero. 159 firms were randomly split into three arms of 53: intensive one-on-one consulting, a cheaper group-based consulting model adapted from agricultural-extension methods, and a control group.

Both treatment arms raised management-practice scores by a similar 8-10 percentage points, about a third of the effect size found in comparable Indian studies. Only the group-consulting arm — roughly a third of the cost of one-on-one consulting — produced a statistically significant increase in firm size (employment up 3-7 workers, or 8-15%) and a non-significant sales increase of 8-9% (p=0.12); individually-consulted firms' outcomes were not statistically distinguishable from the control group. Neither arm showed significant gains in productivity, defect rates or inventory management, and 69% of the original sample was retained through final data collection.

The trial is best read as a direct, randomised cost-effectiveness comparison between two delivery modes for SME management upgrading, rather than proof that either approach transforms firm performance outright; delayed rollout of the group treatment (by more than a year) may also have dampened its measured effect.