目前我正在学习STATA。然后第一次使用STATA做DEA，现遇见个问题：
按照dea函数的命令 .dea employee area= sales profit执行后，出现
invalid syntax
r(198);
的错误。相关附件见下面。请问为何呢，谢谢.
我set trace on 后具体的错误是：------------------------------------------------------------------- begin dea ---
- version 14.0
- if replay() {
  dis as err "ivars and ovars required."
  exit 198
  }
- gettoken word 0 : 0, parse(" =:,")
- while `"`word'"' != ":" & `"`word'"' != "=" {
= while `"employee"' != ":" & `"employee"' != "=" {
- if `"`word'"' == "," | `"`word'"'=="" {
= if `"employee"' == "," | `"employee"'=="" {
  error 198
  }
- local invarnames `invarnames' `word'
= local invarnames  employee
- gettoken word 0 : 0, parse(" :,")
- }
- while `"`word'"' != ":" & `"`word'"' != "=" {
= while `"area="' != ":" & `"area="' != "=" {
- if `"`word'"' == "," | `"`word'"'=="" {
= if `"area="' == "," | `"area="'=="" {
  error 198
  }
- local invarnames `invarnames' `word'
= local invarnames employee area=
- gettoken word 0 : 0, parse(" :,")
- }
- while `"`word'"' != ":" & `"`word'"' != "=" {
= while `"sales"' != ":" & `"sales"' != "=" {
- if `"`word'"' == "," | `"`word'"'=="" {
= if `"sales"' == "," | `"sales"'=="" {
  error 198
  }
- local invarnames `invarnames' `word'
= local invarnames employee area= sales
- gettoken word 0 : 0, parse(" :,")
- }
- while `"`word'"' != ":" & `"`word'"' != "=" {
= while `"profit"' != ":" & `"profit"' != "=" {
- if `"`word'"' == "," | `"`word'"'=="" {
= if `"profit"' == "," | `"profit"'=="" {
  error 198
  }
- local invarnames `invarnames' `word'
= local invarnames employee area= sales profit
- gettoken word 0 : 0, parse(" :,")
- }
- while `"`word'"' != ":" & `"`word'"' != "=" {
= while `""' != ":" & `""' != "=" {
- if `"`word'"' == "," | `"`word'"'=="" {
= if `""' == "," | `""'=="" {
- error 198
invalid syntax
  }
  local invarnames `invarnames' `word'
  gettoken word 0 : 0, parse(" :,")
  }
--------------------------------------------------------------------- end dea ---
r(198);