diff --git a/src/alchemlyb/preprocessing/subsampling.py b/src/alchemlyb/preprocessing/subsampling.py
index 3930b075..824ad8a1 100644
--- a/src/alchemlyb/preprocessing/subsampling.py
+++ b/src/alchemlyb/preprocessing/subsampling.py
@@ -295,6 +295,7 @@ def statistical_inefficiency(df, series=None, lower=None, upper=None, step=None,
             raise ValueError("series and data must be sampled at the same times")
                
         series = slicing(series, lower=lower, upper=upper, step=step)
+        df = slicing(df, lower=lower, upper=upper, step=step)
 
         # calculate statistical inefficiency of series (could use fft=True but needs test)
         statinef  = statisticalInefficiency(series, fast=False)