This fact is from Impression Materials in Dental Materials. It is a commonly tested concept in NEET MDS examinations. Understanding this fact is crucial for answering MCQs correctly.
Addition silicone PVS = most accurate no byproduct
Condensation silicone = releases alcohol byproduct = shrinkage
Polyether = stiffest most hydrophilic = initial rigidity
Alginate = irreversible hydrocolloid = snap set
Agar = reversible hydrocolloid = high detail low strength
Impression plaster = most rigid.