APPENDIX

401

Rating  Formula  I

N-  E
RU

r,  in  which

N  =  number  of  units  covered
E  =»  errors
RU  =  the  number  of  units  called  for  by  the  point  of  reference,
r  =  rating
For  application,  see  rating  of  tests  6  and  8.  When  no  fixed  time
is  set,  but  each  individual  is  allowed  to  complete  the  test  in
his  own  time,  the  equation  becomes:

Rating  Formula  II
Ru  X  RU  -  E  .  ,.,
—  =  r,  in  which
RU  =  the  number  of  units  called  for  by  the  point  of  reference,
in  this  case,  the  entire  test.
Ru  =  reference  time  per  unit,  obtained  by  dividing  the  reference ­
  time  by  the  reference  units  (RU).  In  test  2  this
would  be  35  (reference  time)  4-  50
T  =  time  actually  taken  by  individual  (number  of  cards)  or  .7.
For  application,  see  rating  of  test  2.
Frequently,  accuracy  is  at  a  premium,  and  special  emphasis
is  to  be  placed  upon  mistakes.  This  can  be  done  by  multiplying ­
  E  or  the  number  of  errors  by  2,  3,  4,  or  whatever  value  the
situation  calls  for.  The  general  practice  here  is  to  count  each
error  as  one  unit  and  each  omission  as  one  unit.
The  two  equations  formulated  above  can  be  applied  to  all
tests  in  which  time,  quantity,  and  quality  are  the  factors.
Moreover,  each  equation  can  be  easily  converted  from  a  time
basis  to  a  quantity  basis,  and  vice  versa.  This  is  a  great  advantage ­
  in  handling  data  obtained  under  varying  circumstances.
This  method  of  rating  may  appear  complex  at  the  outset  but
a  little  practice  will  show  it  to  be  extremely  simple  and  easy  of
application.  It  can  be  still  further  simplified  by  the  use  of  tables.