Synchronization complexity is a quantified attribute (see also: measurement

Measurement

Measurement is the process or the result of determining the ratio of a physical quantity, such as a length, time, temperature etc., to a unit of measurement, such as the metre, second or degree Celsius...

) of a characteristic of a concurrent software product. It measures the additional complexity incurred by the synchronization constructs used in the software, and does that by analyzing the software source code. It is essentially an extension of the cyclomatic complexity

Cyclomatic complexity

Cyclomatic complexity is a software metric . It was developed by Thomas J. McCabe, Sr. in 1976 and is used to indicate the complexity of a program. It directly measures the number of linearly independent paths through a program's source code...

for multitasking/multithreaded programs.