Lodged bonds represent the number of tenancy agreements lodged in that month
Active bonds represent the number of tenancy agreements commenced from that month that are still presently active.
Closed bonds represent the number of tenancy agreements from that month that have ended.

Data calculation/treatment

Geometric mean: The geometric mean is calculated by multiplying n values together and taking the nth root of the result. When a variable is log-normally distributed (a common distribution for variables than must be greater than 0) the geometric mean will closely approximate the median.
Synthetic Quartiles (replacing quartiles): The synthetic quartiles are designed to find the 25th percentile (for the lower quartile) and 75th percentile (for the upper quartile) of a set of data, assuming the data is lognormally distributed. The mean and variance of the data are not assumed, but instead are calculated. This approach is consistent with using the geometric mean to approximate the median.

Inclusions

The files include the private bonds, starting from January 1993. 'Private' means private sector landlords.

At URL provided, select 'By territorial authority, January 1993 to September 2023' from under the 'Rental bond data, January 1993 to September 2023 ' heading.