Current commercially available molecular systems and assays are capable of detecting individual target molecules with considerable reliability. As research and diagnostic tests are developed, validated and deployed for use on clinical samples, the need to understand and develop robust statistical analysis routines increases. This talk will cover the fundamental processes and limitations of detecting and reporting at single molecule resolution. It will cover the basics of quantification of targets and sources of imprecision. It will describe the test performance characteristics in the context of counting statistics. It will provide basic guidelines how to determine those, how to choose and interpret the operating point and what factors may influence overall test performance in practice.