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Page Number: 23

6 

KANSAS v. GLOVER 

SOTOMAYOR, J., dissenting 

drunk driving”); Wardlow, 528 U. S., at 124 (permitting of-
ficers to account for the relevant characteristics of a loca-
tion  when  interpreting  whether  flight  from  police  is  “eva-
sive”);  Sokolow,  490  U. S.,  at  9–10 
(crediting  the 
evidentiary significance of facts “as seen by a trained agent” 
to identify a suspicious traveler).  There is no reason to de-
part from that practice here. 

Finally, to bolster its conclusion as grounded in “common 
experience,” the majority cites “empirical studies.”  Ante, at 
4.  But its use of statistics illustrates the danger of relying 
on  large-scale  data  to  carry  out  what  is  supposed  to  be  a
particularized  exercise.    Neither  of  the  referenced  reports 
tells  us  the  percentage  of  vehicle  owners  with  revoked  li-
censes in Kansas who continue to drive their cars.  Neither 
report even offers a useful denominator: One lumps drivers 
with  suspended  and  revoked  licenses  together,  while  the
other examines the license status of only motorists involved
in fatal collisions.  The figures say nothing about how the 
behavior  of  revoked  drivers  measures  up  relative  to  their
licensed counterparts—whether one group is more likely to
be involved in accidents, or whether the incidences are com-
parable—which would inform a trooper’s inferences about
driver identity.

As the concurrence recognizes, while statistics may help
a defendant challenge the reasonableness of an officer’s ac-
tions, they “cannot substitute for the individualized suspi-
cion that the Fourth Amendment requires.”  Ante, at 4–5, 
n.  If courts do not scrutinize officer observation or expertise
in the reasonable-suspicion analysis, then seizures may be
made  on  large-scale  data  alone—data  that  say  nothing
about the individual save for the class to which he belongs.
That analytical approach strays far from “acting upon ob-
served violations” of law—which this Court has said is the 
“foremost method of enforcing traffic and vehicle safety reg-
ulations.”  Delaware v. Prouse, 440 U. S. 648, 659 (1979).