The Data Space

Input data shared by every by-policy projection.

The seven input CSVs are read here, once per model, and referenced from Projection as data. Projection is parameterized by point_id, so each Projection[N] is a separate ItemSpace with its own cells cache; if the readers lived there, every model point would re-read every file. Holding them in an unparameterized Space reads each file once no matter how many policies are projected.

Inputs are external files: plain CSVs in the model folder’s parent directory, products/indexed_ul/, rather than data stored inside the model. The model folder therefore holds nothing but formulas – no _data/, no IOSpec, no embedded values – so a diff of the model shows logic changes only. This follows annuallife.TradLife_A; contrast basiclife.BasicTerm_S, which keeps its inputs inside the model through modelx’s IOSpec machinery.

The consequence worth knowing: the model is not portable on its own. Copying the IUL_US_S folder without its parent’s CSVs produces a model that reads and then fails on first evaluation.

input_dir() resolves the directory from _model.path.parent at run time, so the model works wherever the repository is checked out. Each table has a filename Reference and a reader Cells:

Reference	Cells	File
model_point_file	model_point_table()	model_point_table.csv
coi_rates_file	coi_rates()	coi_rates.csv
corridor_file	corridor_factors()	corridor_factors.csv
mort_table_file	mort_table()	mort_table.csv
class_factor_file	class_factor_table()	class_factor_table.csv
lapse_table_file	lapse_table()	lapse_table.csv
surr_charge_file	surr_charge_table()	surr_charge_table.csv

Two of these are stand-ins for licensed material and are marked [std] row by row in their own provenance columns. coi_rates.csv carries the guaranteed maximum monthly rate per $1,000 of net amount at risk; the notes set that basis at 2017 CSO ANB ultimate [REG-R17], which may not be reproduced here, and the current scale is the guaranteed scale times Projection.coi_curr_factor (65% [std]) because carrier COI tables are not public. mort_table.csv is a small illustrative best-estimate table [std], not the 2015 VBT the notes recommend [REG-R18]; it is the same illustrative table shipped with UL_US_S, so the chassis and this model share a basis.

There is deliberately no premium persistency table. The universal life chassis reads one, because its notes give a 16-row schedule; these notes instead give a closed form – expected premium_y = planned x 0.98^(y-1) – which is implemented as prem_persistency() with the rate in a Reference. Nor is there an index scenario file: the base deterministic run generates index_level() from a level annual return, and a stochastic or historical path is substituted by overriding that one cells.

To swap in a licensed mortality basis, replace mort_table.csv with a same-schema file, or point mort_table_file at a different name, then clear the cache. No formula changes.

Cells Descriptions

input_dir()

The directory holding the input CSVs: the model folder’s parent.

Inputs are external files, not data stored inside the model, so the model folder is pure formulas. The path is resolved at run time from where the model was read, following annuallife.TradLife_A.

model_point_table()

The model point table, read from model_point_table.csv.

coi_rates()

Guaranteed maximum monthly COI rates, read from coi_rates.csv.

Per $1,000 of net amount at risk, keyed by issue-age cell and policy year.

corridor_factors()

The GPT corridor factor table by attained age, read from corridor_factors.csv.

The IRC 7702(d)(2) applicable percentages [R4]: 250% to attained age 40, grading to 100% at 90-95.

mort_table()

The best-estimate annual mortality table by age, read from mort_table.csv.

class_factor_table()

The underwriting-class factors, read from class_factor_table.csv.

lapse_table()

The base annual lapse rates by policy year, read from lapse_table.csv.

surr_charge_table()

The surrender charge schedules, read from surr_charge_table.csv.

One row per surr_charge_id, giving the initial charge per $1,000 of initial face and the number of years over which it runs off linearly.