An adapted Delphi approach: The use of an expert panel to operationally define non-judgment of internal experiences as it relates to mindfulness.

Objectives: There are several definitions of mindfulness throughout the literature, many of which suggest an attitude of non-judgmental awareness. However, the concept of "non-judgment" itself has not previously been systematically operationally defined. Our purpose was to use an expert panel to generate an operational definition of non-judgment of internal experiences, as it relates to mindfulness, to be used to inform the development of an implicit measure of the construct.

Design: We utilized an adapted Delphi survey method consisting of three survey rounds.

Setting: We employed in-person and online survey methods.

Results: We used three survey rounds with an adapted Delphi approach. Expert review panelists consisted of 18 mindfulness researchers or clinicians. Each round of survey results was assessed and discussed among the core team. A consensus was reached among the core team for an operational definition of non-judgment of internal experiences: "acknowledging our thoughts, feelings, and sensations, as they are, without applying valence (e.g., good, bad, right, wrong) to them."

Conclusions: An expert panel review process informed the generation of an operational definition of non-judgment of internal experiences. Our operational definition provides a foundation for the future development of an implicit task of non-judgment of internal experiences, with the aim of using this task to assess change in response to mindfulness-based treatments. To our knowledge, this is the first systematic definition of non-judgment of internal experiences within the mindfulness literature.