Four conditions influence the effectiveness of an encoded message: the skills, attitudes, and knowledge of the sender, and the

Beyond the sender's skills, attitudes and knowledge, the fourth condition shaping an encoded message is the social-cultural system.

This draws on Berlo's SMCR model, where the source's social system and culture govern how a message is framed.

Limiting the fourth factor to the receiver's knowledge alone misreads the model, since it lists source-side conditions.

The age of the sender is not one of Berlo's named source factors, so it does not complete the set.

Environmental issues are external noise rather than an encoding condition seated in the sender.

Skills, attitudes, knowledge and the social-cultural system together decide how well a source encodes.