1. A method for determining a system performance indicator representative of the overall operation of a network system, the method comprising: obtaining, by a performance analysis server from a plurality of infrastructure elements included in a network system, performance metric data associated with a plurality of application processes being executed by the plurality of infrastructure elements, wherein the performance metric data includes both a service time and a transaction response time for each of the plurality of application processes, wherein the service time is an amount of time an infrastructure element executes an application process and the transaction response time is an amount of time between when the infrastructure element receives a query for executing the application process and when the infrastructure element sends a response to the query, wherein the plurality of infrastructure elements includes computer servers that provide the performance metric data to the performance analysis server in a contemporaneous manner; consolidating, by the performance analysis server, analogous portions of the performance metric data into a service time data group and a transaction response time group irrespective of the plurality of infrastructure elements; utilizing, by the performance analysis server, both the service time data group and a transaction response time group to determine a system performance indicator (SPI) value that represents an overall performance level of the network system; and presenting, by the performance analysis server, the determined SPI value to a user via a user interface or display.