Infant Behavior and Development reports on research on fine and gross motor skill testing in infants and young children.  The study indicated during infancy predictive fine and gross motor scores were non linear.  During the preschool years, predictive gross motor scores were non linear and fine motor scores were more linear.   Girls had higher percentiles for fine motor skills in infancy and preschool years.  The authors recommend that children should be studied over time for fine and gross motor scores rather than a single test. 

Reference:  Johanna Darrah, Ambikaipakan Senthilselvan and Joyce Magill-Evans  (2009)  Trajectories of serial motor scores of typically developing children: Implications for clinical decision making  Infant Behavior and Development Volume 32, Issue 1, January 2009, Pages 72-78