An index that well reflects the difficulty of ground deployment testing is the ratio of gravity force to deployment force. The object of this study is to quantitatively clarify the relationship between the difficulty index and the accuracy with which deployment force can be evaluated. We perform ground deployment tests using a simple planar truss in micro gravity and gravity environments. Ground tests in which the difficulty index value of the planar truss is increased are also performed. By comparing the experimental and analysis results, we quantitatively evaluate the difficulty index and the accuracy with which the deployment force can be estimated from ground testing. We introduce an index that indicates the size limit of deployable structures up to which ground test evaluations remain accurate.