On the wider web, your search helps bring back to this site and its collective, the following, remixed in descending order of brevity and utility; multiple sources suggest this concept and primary diagram were developed by Chris Argyris then presented by Peter Senge in The Fifth Discipline.
Ladder of Inference: Short Circuiting Reality, One Screen, Three Images
Gene Bellinger, showing how beliefs & assumptions lead to data exclusion
Up and Down the Ladder of Inference (Best Look at Role of Diversity in Group Thinking)
Bob Larcher, January 2007, PDF Three Pages
The Ladder of Inference (Original Excerpt), One Screen, No Images
Senge, Kleiner, Roberts, Ross, Smith, The Fifth Discipline Fieldbook, 1994
The Ladder of Inference: How assumptions can cause miscommunication
Yvonne F. Brown, JAD Communications International, 7 pages, undated
Phi Beta Iota: Crowd-sourcing is one means of achieving diversity; having tools for sharing and collective sense-making is helpful, as is a strategic analytic model that provides efficiencies in connecting dots to dots, dots to people, and people to people. “Root” for this concept is “everything, always.” It is not possible to fully appreciate any set of data, assumptions, and derived meanings in isolation. This is why the fragmentation of knowledge is killing us.