The field testing of the ICD-10 multiaxial system was organized as a WHO-coordinated project comprising two international field trials of the applicability, feasibility and reliability of the proposed ICD-10 schema. The specific objectives of the first field trial were: (i) to assess the applicability and ease of use of the ICD-10 multiaxial schema in the daily work of psychiatrists and other mental health professionals; (ii) to determine the perceived usefulness of the multiaxial presentation of ICD-10 for: (a) support of decisions regarding regular patient care; (b) training of mental health professionals; (c) research on mental disorders; and (d) statistical reporting and other public health purposes; (iii) to identify problems experienced in the use of the ICD-10 multiaxial schema; (iv) to obtain an estimate of the inter-rater reliability for each of the axes of the ICD-10 multiaxial schema. The second field trial was aimed at exploring the consequences of the amendments made to the ICD-10 multiaxial system after the analysis of results of the first field test.

The ICD-10 multiaxial field trials package consisted of the following documents: (1) Field Trials Protocol, specifying the phases of work and assessment procedures; (2) Case Study Form, intended for recording the assessment and comments of each clinician for each case; (3) Final Comments Form, intended for clinicians' overall rating of and comments on the ICD-10 multiaxial schema after their completion of the field trial; (4) ICD-10 CDDG, containing detailed descriptions of ICD-10 mental and behavioural disorders as well as a listing of other (i.e., physical) disorders and conditions that were found to be often associated with the disorders included in ICD-10 Chapter V itself; (5) WHO Disability Diagnostic Scale (WHO DDS), with brief guidelines for its use and rating instructions;