Management: Human Resource Management $-$ Employee Turnover

As organizational commitment is generally measured through self$-$report questionnaires, why would there be an argument for taking colleagues' views into account also?

A $$ Self$-$report measures have sensitive psychometric properties.

B $$ Intention to leave is strongly correlated with low organizational commitment.

C $$ We might be biased whereas colleagues might be more objective.

D $$ An individual will know more about their organizational commitment than anyone else.