Background: Evaluative thinking is rigorous analysis of evidence and reasoning to inform judgments of merit, worth, value, significance, and utility. Although formal concepts and definitions for evaluative thinking have only emerged recently, its practice has been around for many years. In-depth historical case studies of international evaluations using evaluative thinking principles are rare, especially the ones reported by those who were involved a half-century ago.
 Purpose: This article describes little-known but historically significant educational reform initiative in Guinea Bissau (West-Africa) in the 1970s supported by a group led by Paulo Freire, examining what occurred through the lens of evaluative thinking.
 Setting: In 1975, Freire and the Idac team were invited to develop a national adult literacy campaign in Guinea Bissau. Freire was already well known for his revolutionary ideas in “Pedagogy of the Oppressed.”
 Intervention: Idac team supported the government to adopt Freire’s education and action approach comprising three core strategies: (i) critically understand reality, (ii) conduct scientific studies and (iii) application of the new knowledge. While Freire and four senior members of Idac’s team visited the country every three months, two other members lived there for four years. The decision was to invest in experimental pilot projects while reforming what was possible within the existing traditional school curricula.
 
 
 Research Design: The authors conducted a retrospective developmental evaluation exemplifying what can be learned by examining past events through contemporary concepts.
 Data Collection and Analysis: In-depth interviews were conducted with key informants, especially Claudius Ceccon (one of the authors) who was a senior member of the Idac team working with Paulo Freire in Guinea Bissau. Also, several project original documents and relevant publications were reviewed. Thick description and content analysis were used to revisit that educational reform and examine its implications for evaluative thinking.
 Findings: Even though Freire’s most prominent ideas were developed before evaluation was considered as an established field, his approach of dialectic inquiry, critical reflection and taking action has influenced and still influences many leading scholars and practitioners within our (trans)discipline. While Freire did not use the phrase “evaluative thinking,” his process of critical engagement with local people to analyze and understand their situation and take action based on their reflections manifests core elements of what today would be considered embedded evaluative thinking. In political reforms around the world, the retrospective evaluation of what happened in Guinea Bissau reminds us of the importance of evaluative thinking and reflective dialogue – and the fragility of both in the face of political polarization and changes in leadership.
 
 
 
 
 Keywords: Paulo Freire; evaluative thinking; developmental evaluation; retrospective studies; Guinea Bissau.