The best way to map youth members skills and achievements is by using the S2P convertor as well as having a discussion with the Scout.
The S2P convertor will map old award scheme achievements across to the Outdoor Adventure Skills however Scouts will have skills that were not part of the previous award scheme that are part of the Outdoor Adventure Skills. To fill these gaps have the Scouts read through the Outdoor Adventure Skills stages and self-assess where they believe their skills are then take this assessment, along with evidence they may have, to their Unit Council for review. For younger Scouts leaders and parents can assist in this.
It is important to note that even though a Scout may have completed I-statements in a higher Stage they must have been able to show competency in all the I-statements of the lower Stages as well.