Match Function - no room for error

[Dee Veloper]

[i apologize if this is posted twice, posting from google and got
error messages]

I'm working with an application that deals with very unstructured
data.
I'm going to use lookup functions and countiff to make sense of the
data...but there is no room for error..

if i use the function =MATCH(Selected,mylist,0) to identify the first
occurence of the text found in "Selected", can I be 100% sure that the
value returned will be the first row the value is found? For example
below if Selected=Jones I must return 1.

for example
mylist
Jones 1000 <---- must return 1 given this is first item
Jones 2000
Jones 3000
Smith 2000

is it foolproof?
thanks