GEMs are only able to provide a general approximation between the diagnoses codes in ICD-9-CM and ICD-10-CM. Why is this?

What will be an ideal response?

Answer: They are only able to provide a general approximation between the
two code sets because there are so many more codes in ICD-10-CM/PCS than in
ICD-9-CM. ICD-9-CM has approximately 16,000 codes. ICD-10-CM has
approximately 68,000. ICD-10-CM is much more specific than ICD-9-CM.