New version of hillmaker (finally) released - and it’s Python

Goodbye, Access, you’ve been great


Mark Isken


January 22, 2016

UPDATE 2023-01-16

See for latest version.

Back in March of 2013, I did the first hillmaker related blog post. As way of background on hillmaker, here’s the opening of that post:

Many years ago I created an MS Access add-in called Hillmaker for doing time of day and day of week based occupancy analysis in health care delivery systems. A typical use would be to find the mean and 95th percentile of occupancy in a set of nursing units or an emergency department. Hillmaker was released as an open source project back in 2005 and has gotten quite a bit of use. However, I never really did any more development on it even though there were a number of enhancements that I (and many others) would like to have seen. The only attention it has gotten from me was in response to the object library problems caused by new releases of MS Office. No fun.

In that post and in two follow up posts I hacked out a proof of concept version of hillmaker using Python and developed matplotlib recipes for creating occupancy plots based on hillmaker output.

Since that time I’ve chipped away at a Python based version hillmaker. It’s finally in a state that I feel comfortable releasing. Still many improvements to make but core functionality is there.

The main project GitHub repo is at

So, here’s the content of the README file that comes with hillmaker.


hillmaker is a Python package that computes time of day and day of week specific occupancy statistics from transaction data containing arrival and departure timestamps. Typical use is for capacity planning problems in places like hospital emergency departments, surgical recovery rooms or any system in which entities arrive, occupy capacity for some amount of time, and then depart. It gets its name from the hill-like nature of plots based on temporal occupancy statistics.

Occupancy Plot

A few features of the new hillmaker include

  • Takes a pandas DataFrame as the input data type
  • Functions for computing arrival, departure and occupancy summary statistics by time of day, day of week, and entity category based on a pandas DataFrame containing one record per visit.
  • Functions for computing arrival, departure and occupancy for each datetime bin in the analysis period, by category.
  • Select any time bin size (minutes) that divides evenly into a day.
  • Optionally specify one or more categories to ignore in the analysis.
  • Output statistics includes sample size, mean, min, max, standard deviation, coefficient of variation, standard error, skew, kurtosis, and a whole slew of percentiles (50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 97.5, 99).
  • Output CSV files are written by default but can be supressed.
  • Optionally capture outputs as a dictionary of pandas DataFrames for further post-processing (e.g. plot creation).
  • Requires Python 3 and pandas
  • Apache 2.0 licensed

Quick Start

UPDATE 2023-01-16

Everything below is out of date. See for latest version.

A companion repo, contains IPython notebooks and Python scripts illustrating the use of hillmaker.

In particular, the following IPython notebooks explains how to get and use hillmaker.

For Windows

For others

Both Win-64 and Linux-64 versions are available. :

conda install -c hillmaker

The source and a binary wheel are available from PyPi. You can install using pip: :

pip install hillmaker

More examples and documentation are on the way.