**Definition:**

Residual factor R for reflections that satisfy the resolution limits established by _refine_ls_shell.d_res_high and _refine_ls_shell.d_res_low and the observation limit established by _reflns.observed_criterion, and that were used as the test reflections (i.e. were excluded from the refinement) when the refinement included the calculation of a 'free' R factor. Details of how reflections were assigned to the working and test sets are given in _reflns.R_free_details. sum|F~obs~ - F~calc~| R = --------------------- sum|F~obs~| F~obs~ = the observed structure-factor amplitudes F~calc~ = the calculated structure-factor amplitudes sum is taken over the specified reflections

**Type:** float

**Mandatory item:** no

The permitted range is [0.0, infinity)

**Related items: **_refine_ls_shell.wR_factor_R_free (alternate)

_refine_ls_shell.R_factor_R_free_error (associated_error)

**Category:** refine_ls_shell

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