Function reference • ccao

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_check_class()`	Check if a property class falls within its expected square footage and age boundaries
`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
`class_dict`	Data dictionary of Cook County property classes
`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

Reference

Functions

Measure assessment performance

Format data

Lookup values

Manage characteristics

Adjust estimated values

Miscellaneous functions

Data

Dictionaries

Spatial data

Sample data

Miscellaneous