Hansson and Polk (2018, Research Evaluation, 27/2: 132–44) aim to assess the usefulness of the concepts of relevance, credibility, and legitimacy for understanding the link between process and impact in transdisciplinary (TD) research. However, the article misrepresents some of the ideas in the two main reference articles. It also uses definitions of the concepts it aims to test that are inconsistent with the definitions offered by the reference papers. The methods description is insufficient to know what data were collected or how they were analyzed. More importantly, the effort to understand relationships between process and impact in TD research needs more careful definitions of the concepts outcome and impact as well as more objective ways to assess outcomes and impacts. This letter discusses shortcomings in the article and makes suggestions to improve conceptual clarity and methods for empirically assessing TD research effectiveness.								
								
									Authors:
									Belcher, B.; Ramirez, L.F.; Davel, R.; Claus, R.								
																
									Subjects:
									research, impact								
															
									Publication type:
									Evaluation report, ISI, Journal Article, Publication								
																
									Year:
									2019										
								
								
																		ISSN:
									0958-2029								
																
								 
						 Restoration
																	Restoration																 Plantations and tree crop commodities
																	Plantations and tree crop commodities																 Enhanced nutrition and food security
																	Enhanced nutrition and food security																 Biodiversity, safeguarding and conservation
																	Biodiversity, safeguarding and conservation																 Nationally determined contributions
																	Nationally determined contributions																 Bioenergy and biomaterials
																	Bioenergy and biomaterials																 Blue carbon and peatlands
																	Blue carbon and peatlands																 Climate change adaptation
																	Climate change adaptation																 Landscape governance
																	Landscape governance																 Gender
																	Gender																 Silvopastoral systems
																	Silvopastoral systems																 Market-based agroforestry-forestry
																	Market-based agroforestry-forestry																 Farm-forest policy interface
																	Farm-forest policy interface																 Agroecology
																	Agroecology																 Livelihood trajectory modelling and assessment
																	Livelihood trajectory modelling and assessment																 Inclusive finance and business models
																	Inclusive finance and business models																 Innovating finance for sustainable landscapes
																	Innovating finance for sustainable landscapes																 Public and private commitments to zero deforestation
																	Public and private commitments to zero deforestation																 Orphan tree crops
																	Orphan tree crops																 Effectiveness of approaches to sustainable supply
																	Effectiveness of approaches to sustainable supply																 Quality of FTA research for development
																	Quality of FTA research for development																 Sentinel landscapes
																	Sentinel landscapes																 Foresight
																	Foresight																 Seeds and seedlings delivery systems
																	Seeds and seedlings delivery systems																 Smallholder tree-crop commodities
																	Smallholder tree-crop commodities																 
																	 
																	 
																	 
																	 
																	 
																	 
																	 
																	 
																	 
					  							 
					  							 
					  							 
					  							 
					  							