I have created a web application. One of the feature is text search which perform the boolean operator ( NOT, AND, OR) as well. However, I have no idea on calculating the search's accuracy and efficiency.

For example:

1 . Probe identification system for a measurement instrument

2 . Pulse-based impedance measurement instrument

3 . Millimeter with filtered measurement mode

when the user key in will return the result as below

input :measurement instrument

Result: 1,2

input : measurement OR instrument NOT milimeter

Result: 1,2,3

so, i have no idea on what issue and what algorithm to calculate on the accuracy and efficiency of the text search.. anyone have any idea on that?