Reference

Functions
Measure assessment performance Calculate assessment performance statistics in accordance with the CCAO Data Science Department’s Standard Operating Procedure on Sales Ratio Studies. The main changes are enforcement of outlier trimming (top and bottom 5% of ratios are always dropped) and a strict minimum sample size (N must be >= 30). Each function outputs a named list containing the statistic, its confidence interval, whether or not the IAAO standard was met, and the number of observations used to calculate the statistic.
ccao_cod() ccao_prd() ccao_prb()	Calculate sales ratio statistics using CCAO SOPs
Format data Clean and format Property Index Numbers (PINs)
pin_clean()	Remove separators and whitespace from input PIN(s) and warn if invalid
pin_format_pretty()	Add dash separators to input PIN(s)
Lookup values Convert between township names, assessment years, and triads
town_convert()	Convert from township name to township number and visa versa
town_get_assmnt_year()	Get the nearest assessment year of a township
town_get_triad()	Get Cook County triad name or number based on township name or code
Manage characteristics Recode/rename characteristic columns, merge HIE data, and fix characteristic errors
chars_288_active()	Return active years given a 288 start date and township
chars_fix_age()	Fix the age variable in CCAO data
chars_sparsify()	Convert ADDCHARS SQL data to a sparse format that can be joined to other data
chars_update()	Update characteristic values using joined values from ADDCHARS
vars_recode()	Replace numerically coded variables with human-readable values
vars_rename()	Bulk rename variables from CCAO SQL to standardized or pretty names and visa versa
Adjust estimated values Apply post-modeling adjustments to raw model values
val_round_fmv()	Round model values to flat amounts
val_limit_ratios()	Limit excessive sales ratios
Miscellaneous functions Functions with no other suitable category
ccao_generate_id()	Generate a memorable ID string based on CCAO employee names
Data
Dictionaries Lookups for numeric codes used in the assessment system
cdu_dict	Data dictionary of codes used to identify specific property situations
coe_dict	Data dictionary of Certificate of Error reason codes
town_dict	Data dictionary for CCAO township codes and triads
vars_dict	Data dictionary for CCAO data sets and variables
vars_dict_legacy	Data dictionary for legacy CCAO data and variables
Spatial data CCAO-specific spatial boundaries. Must load sf library before using
nbhd_shp	Simple features (sf) data frame of CCAO neighborhoods
town_shp	Simple features (sf) data frame of Cook County townships
Sample data Sample data frames pulled directly from CCAO SQL or Athena
chars_sample_athena	Sample dataset from the vw_card_res_char Athena SQL view
chars_sample_hie	Sample dataset from the ccao.hie Athena SQL table
chars_sample_universe	Sample dataset from the VW_RES_UNIVERSE SQL view
Miscellaneous Other data used throughout the department or in specific functions
ccao_colors	Official CCAO color palette
chars_cols	List crosswalk of Athena columns and their ADDCHARS equivalents