The property BuildMethod specifies the method that is used to build a complete mortality curve from a finite set of death rates or survival probabilies. The table below gives the BuildMethods currently supported

BuildMethod Description
CONSTANT_FORCE Between age nodes the force of mortality is constant
QUADRATIC_FORCE Between age nodes the force of mortality is a quadratic function of age with curvature continuous across age nodes.
HYBRID_FORCE Between age nodes the force of mortality is a quadratic function of age. Force does not vary as much as for QUADRATIC_FORCE but curvature is discontinuous across nodes.
HELIGMAN_POLLARD Fit death probabilities using the 9-parameter Heligman-Pollard model.
SMOOTHED_ASDR Build the curve using HYBRID_FORCE then smooth death rates using P-Splines.
CALIBRATED_SPLINE Fit the curve with B-splines to maximise projection onto calibrated set of shapes.
HELIGMAN_POLLARD8 Fit death probablities or death rates using the 8-parameter Heligman-Pollard model.
ADJUSTED_HELIGMAN_POLLARD8 Build mortality curve by first fitting death probablities or death rates using the 8-parameter Heligman-Pollard model then adding spread to the force of mortality to match curve imputs.
NIDI Fit death probablities or death rates using the 10-parameter model developed by the Netherlands Interdisciplinary Demographic Institute.
ELANDT_JOHNSON Build mortality curve using using the Elandt-Johnson method.
CUBIC_SF Interpolate survival fractions with cubic splines.
MOD_QUADRATIC_FORCE Same as QUADRATIC_FORCE except the first two ages are used to fit the NIDI childhood model.
LINEAR_SF Linearly interpolate survival fractions.
LINEAR_INVSF Linearly interpolate the inverse survival fractions.
HERMITE_SF Interpolate person-years lived and survival fractions with cubic Hermite splines.
HERMITE_FORCE Interpolate person-years lived and survival fractions with piecewise linear force.
TOPALS Build a curve using TOPALS regression
BRASS Survival fractions are fitted using the Brass relational model
ABS_SPREAD Between age nodes the force of mortality is a constant additive spread relative to a standard mortality curve.
REL_SPREAD Between age nodes the force of mortality is a constant multiplicative spread relative to a standard mortality curve.
SVM A non-parametric fit to mortality rates using Support Vector Machine regression
KERNEL_REGRESSION A non-parametric fit to mortality rates using kernel regression
PTOPALS A relational model that builds the mortality curve using TOPALS and P-Splines
PCLM Expand an abridged death rates using the Penalised Composite Link Model
CODE Fit death probablities or death rates using the 10-parameter CoDe model.

For mortality objects with a DeathRatios subtable MultiDecBuildMethods build complete cause-specific mortality curves from a finite set of death ratios.