Assessors were masked to group allocation?

Does "assessors were masked to group allocation" mean "assessors were refrained from knowing the condition of group allocation"?

Context:

Summary

Background

Observational evidence suggests that community-based services for people with schizophrenia can be successfully provided by community health workers, when supervised by specialists, in low-income and middle-income countries. We did the COmmunity care for People with Schizophrenia in India (COPSI) trial to compare the effectiveness of a collaborative community-based care intervention with standard facility-based care.

Methods

We did a multicentre, parallel-group, randomised controlled trial at three sites in India between Jan 1, 2009 and Dec 31, 2010. Patients aged 16—60 years with a primary diagnosis of schizophrenia according to the tenth edition of the International Classification of Diseases, Diagnostic Criteria for Research (ICD-10-DCR) were randomly assigned (2:1), via a computer-generated randomisation list with block sizes of three, six, or nine, to receive either collaborative community-based care plus facility-based care or facility-based care alone. Randomisation was stratified by study site. Outcome assessors were masked to group allocation. The primary outcome was a change in symptoms and disabilities over 12 months, as measured by the positive and negative syndrome scale (PANSS) and the Indian disability evaluation and assessment scale (IDEAS). Analysis was by modified intention to treat. This study is registered as an International Standard Randomised Controlled Trial, number ISRCTN 56877013.