I need some way to allow all users to view certain fields but only allow admin to edit them.

I know it is rather easy to hide fields from the user but make them available to anyone with admin permission. What I need is the ability to show a field to all users but only allow editing of this field by those with admin permissions.

For example... a field to show a members rating within an organization. I need field to be available for all to view and search for...... but only allow it to be modified by admin permission.

Is it possible to alter the modify sub to allow modifications to certain fields only by admin? Yet still allow global view?