depreciation_interest: Annual depreciation + interest for medical equipment

In tatooheene: Technology Appraisal Toolbox for Health Economic Evaluations in the Netherlands

Annual depreciation + interest for medical equipment

Description

Compute the annuity factor and the annual depreciation-and-interest charge for medical equipment, following Section 7.3 of the Dutch costing manual; k = annual depreciation and interest expense jaarlijkse afschrijvings- en rentekosten

Let V be replacement value, R the salvage value, n the amortisation period (years), and i the interest rate (per year). The annuity factor is:

a_{n,i} = \frac{1}{i}*\bigg(1-\frac{1}{(1 + i)^{n}}\bigg)

#' The annual charge k is:

k = \frac{V - \frac{R}{(1 + i)^n}}{a_{n,i}}

Usage

depreciation_interest(
  v_replace_val,
  r_salvage_val,
  n_amortisation_period = 10,
  i_interest_rt = 0.025,
  output = c("dataframe", "annuity_factor", "annual_cost")
)

Arguments

v_replace_val	V: vervangingswaarde; replacement value (numeric scalar, > 0)
r_salvage_val	R: restwaarde; salvage (residual) value at end of period (numeric scalar, >= 0)
n_amortisation_period	n: afschrijvingstermijn; amortisation period in years (numeric scalar, > 0)
i_interest_rt	i: rentepercntage; annual interest rate as a decimal (numeric scalar, >= 0)
output	One of dataframe (default), annuity_factor, or annual_cost.

Value

• If output = "dataframe": a data.frame with two columns: ⁠Annuity factor⁠ and ⁠Yearly depreciation and interest costs⁠.

• If output = "annuity_factor": a single numeric (the annuity factor).

• If output = "annual_cost": a single numeric (the annual charge k).

Examples

# Both values as a data frame (defaults: n=10, i=2.5%)
depreciation_interest(v_replace_val = 50000, r_salvage_val = 5000)

# Only the annuity factor
depreciation_interest(50000, 5000, output = "annuity_factor")

# Only the annual charge (k)
depreciation_interest(50000, 5000, output = "annual_cost")

# Zero interest (uses the i -> 0 limit): a = n, k = (V - R)/n
depreciation_interest(50000, 5000, n_amortisation_period = 8,
                      i_interest_rt = 0,
                      output = "dataframe")

tatooheene documentation built on Dec. 15, 2025, 5:06 p.m.