It is known that with the formula that accounts for the time dilation effect in hand we can derive directly the formula that accounts for the length contraction effect: L0/Dt=L/(Dt)0 (1) where L0 and (Dt)0 are proper length and proper time intervals, L and Dt representing measured length and coodinate time interval. From (1) L=L0(1-V2/c2)1/2 (2) Is there a special reason (Ockham's razor) for deriving (2) involving the Lorentz transformations and to perform a simultaneous detection of the space coordinates of the moving rod? I find in the literature of the subject derivations of (2) considering that the two ends are detected at different times. Does the simple derivation (2) involve simultaneous detection of the ends of the rod? Thanks for your answer.