Sampling depth (also called sequencing depth or → library size) is the number of sequenced bases for a given sample.
Increase in sampling depth in recent years
Shotgun metagenomic sequencing - human gut
Average sample size of whole-genome sequencing (WGS) samples of human gut metagenomes deposited at the NCBI short read archive. Median run size of each study was chosen to avoid dominating the results by larger studies.
How deep is enough for metagenomic shotgun sequencing?
It's a balance between sampling depth and number of samples (for a given budget).
Increasing sampling depth
led to increased detection of bacterial species and strains at lower abundance level.
Higher number of samples
will increase the statistical power to proof that our experimental findings are correct.
Ni et al., 2013. Scientific Reports
Statistical sample sizes and power calculations