Assessment of Articulation and Phonological Disorders
Read the section titled "Formal Assessment Measures" beginning on page 155 and ending on page 158. Read the third bullet point on the right side of page 153 starting with "Severity measures." (10 minutes)
ResearchGate - 2011
Click https://www.researchgate.net/publication/272415388_Assessment_of_Articulation_and_Phonological_Disorders link to open resource.