An inquiry is a combination of input and output, where user sends some data to inquire about as input and the system responds to the user with the output of inquiry processed. The complexity of a query is more than External Input and External Output. Query is said to be unique if its input and output are unique in terms of format and data.

●      Simple – if query needs low processing and yields small amount of output data

●      Complex – if query needs high process and yields large amount of output data

●      Average – in between simple and complex.

Each of these parameters in the system is given weightage according to their class and complexity. The table below mentions the weightage given to each parameter:

Parameter	Simple	Average	Complex
Inputs	3	4	6
Outputs	4	5	7
Enquiry	3	4	6
Files	7	10	15
Interfaces	5	7	10

The table above yields raw Function Points. These function points are adjusted according to the environment complexity. System is described using fourteen different characteristics:

●      Data communications

●      Distributed processing

●      Performance objectives

●      Operation configuration load

●      Transaction rate

●      Online data entry,

●      End user efficiency

●      Online update

●      Complex processing logic

●      Re-usability

●      Installation ease

●      Operational ease

●      Multiple sites

●      Desire to facilitate changes

These characteristics factors are then rated from 0 to 5, as mentioned below:

●      No influence

●      Incidental

●      Moderate

●      Average

●      Significant

●      Essential

All ratings are then summed up as N. The value of N ranges from 0 to 70 (14 types of characteristics x 5 types of ratings). It is used to calculate Complexity Adjustment Factors (CAF), using the following formulae:

CAF = 0.65 + 0.01N

Then,

Delivered Function Points (FP)= CAF x Raw FP

This FP can then be used in various metrics, such as:

●      Cost = $ / FP

●      Quality = Errors / FP

●      Productivity = FP / person-month