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Explore an alternative reserving method for motor liability claims using the Deterministic Individual Claim Development (ICD) methodology. This method estimates future claim payments based on historical individual incremental claim payments, without aggregating the data.
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Individual Claim DevelopmentAn Application Bas Lodder 9 March 2015
Chain LadderBasedMethodsLimitations • Classicalchainladder (CL) basedclaimreservingmethodsarestandardpracticefor • attritionalclaims • large volumes • historicallyhomogeneousrisks • claimswithexpecteddevelopmentbased on AY / DY only (nocalendaryeareffect) • sufficienthistoricalclaimsinformation • Counterexample: motorliability • includes large claims • claiminflationeffects • propertydamage vs. bodilyinjury general non-homogeneity • changes in legal environment (whiplash, „Via sicura“) historical non-homogeneity • lump-sumandannuitypayments shocks, complextailbehaviour Weneedto find an alternative reservingmethodformotorliabilityclaims Individual Claim Development - Bas Lodder, 09/03/2015
Alternative Claim ReservingMethodsIndividual Claim Development • Classical CL methodsaggregatehistoricalclaimpayments per risk in an AY – DY triangle • Can weimproveourestimatesifweskiptheaggregationstep? • Option 1: deterministic individual claimdevelopment • triangulation: similartoclassical CL methods • bestestimatebynearestneighbourapproach • Option 2: stochastic individual claimdevelopment • triangulation: developmentpatternbased on numberofpayments per claim • stochasticsimulationoffuturepayments (frequencyandseverity) • literature: Antonio et al. (2012), Pigeon et al. (2013), Pigeon et al. (2014) • Weneed a secondopinionforour CL bestestimate Chosen method: deterministic individual claimdevelopment Individual Claim Development - Bas Lodder, 09/03/2015
Deterministic Individual Claims Development (ICD) Methodology • Givenhistorical individual incrementalclaimpaymentsCi,k, weneedtoestimatefutureclaimpaymentsĈi,kforeachclaimiandeach DY k ≤ kmax = maxk(Ci,k) • Ĉi,k = αi,k * Σj: AY(j) + k ≤ CY((Di,j)β * Cj,k), with • Di,j = distancemeasurebased on historicalclaimdevelopmentdifference • αi,k= 1 / (Σj: AY(j) + k ≤ CY((Di,j)β ) (scalefactor) • βϵ (-∞, 0) (shapefactor) • Options forcalculatingDi,j • claimsbasis: paidorincurred • method: additive ormultiplicative • differences: absolute orsquared k (DY) Ci,k AY, i CY Ĉi,k Individual Claim Development - Bas Lodder, 09/03/2015
Deterministic Individual Claims Development (ICD) Example • First wecalculatethedistancesDi,j: • D3,1 = │C3,0 - C1,0│ + │C3,1 - C1,1│ = │10 - 40│ + │40 - 80│ = 70 • Similarly, we find D3,2 = 30, D4,1 = 20, D4,2 = 20 andD4,3 = 10 • Next, wecalculatethescalingfactorsαi,k, with, say, β = -1 andβ = -2 • β = -1: α3,2 = 1 / (1/D3,1 + 1/D3,2) = 1 / (1/70 + 1/30) = 21 • β = -2: α3,2 = 1 / (1/(D3,1)2 + 1/(D3,2)2) = 1 / (1/4900 + 1/900) = 44100 / 58 ≈ 760 • Similarly, we find α4,1 = 5 resp. 66.7 andα4,2 = 10 resp. 200 • Now, wederivetheexpectedclaimpaymentsĈi,k(forsakeofsimplicity, wetakeβ = -1) • Ĉ3,2 = α3,2 * (C1,2/D3,1 + C2,2/D3,2) = 21 * (0/70 + 40/30) = 28 • Ĉ4,1 = α4,1 * (C1,1/D4,1 + C2,1/D4,2 + C3,1/D4,3) = 5 * (80/20 + 60/20 + 40/10) = 55 • Ĉ4,2 = α4,2 * (C1,2/D4,1 + C2,2/D4,2) = 10 * (0/20 + 40/20) = 20 28 55 20 Di,jisconstant in k, αi,kis not! Individual Claim Development - Bas Lodder, 09/03/2015
ICD: An ApplicationProcess, Data, Assumptions • Model implementationwith Frank Cuypers and Simone Dalessi, Prime Re Services • methodology • VBA-based Excel template • testingloops • Data andassumptions in thispresentation • inputdata: large (0.2 – 1.0 MCHF) andmid-size (0.1 – 0.2 MCHF) Swiss Mobiliar motorliabilityclaims • claimsbasis: paid • method: additive • differences: absolute • β = -2, i.e. Ĉi,k = αi,k * Σj: AY(j) + k ≤ CY((Di,j)-2 * Cj,k) Individual Claim Development - Bas Lodder, 09/03/2015
Mid-sizeclaims – Actual vs. Expected, CY 2014500 claims • Althoughclaimamountsvaryby AY, both CL and ICD estimatesseemtobequiteaccurate Individual Claim Development - Bas Lodder, 09/03/2015
Mid-sizeclaims – Estimation Error, CY 2014500 claims • Large historicalsingleclaimpaymentscauseoverestimation in AYs 2002-2004 • ICD outperforms CL in these AYs sinceitputsnegligibleweight on theclaimforwhichthesepaymentsweremade • Other claimdevelopmentscausesimilarestimationerrorstobothmethods Individual Claim Development - Bas Lodder, 09/03/2015
Mid-sizeclaims – Actual vs. Expected, CY 201460 claims • Werandomlypicked 4 claims per AY toreducethenumberofclaims • The smallernumberofclaimscausesshocks in claimpayments • The shock in AY 2004 was knownby CY 2011, theone in AY 2008 camelater Individual Claim Development - Bas Lodder, 09/03/2015
Mid-sizeclaims – Estimation Error, CY 2014 60 claims • Due tothesmallernumberofclaims, deviationsfromactualpaidamountsare larger • In particular, thepayment in DY 5 of AY 2008 cameunexpected • Contrarytoouroverallexpectationofsmallerdatasets, ICD does not significantlyoutperform CL in thisexample, exceptfor AYs 2009 and 2010 Individual Claim Development - Bas Lodder, 09/03/2015
Large claims – Actual vs. Expected, CY 20141‘600 claims • The declinepaidclaimamountsiscausedby • Decline in whiplashclaims • Difference in claimmaturity Individual Claim Development - Bas Lodder, 09/03/2015
Large claims – Estimation Error, CY 20141‘600 claims • The decline in whiplashclaimscauses large estimationerrors in bothmethods • Otherwise, ICD performsslightlybetterhere Individual Claim Development - Bas Lodder, 09/03/2015
Large claims – Actual vs. Expected, CY 201460 claims • The decline in claimspaymentsover time ismostlycausedbyfrequencyandthereforethereduceddataset (4 claims per AY) is not affected Individual Claim Development - Bas Lodder, 09/03/2015
Large claims – Estimation Error, CY 201460 claims • As expected, thereductionofclaimscauses larger estimationerrors • ICD still performsslightlybetterthan CL Individual Claim Development - Bas Lodder, 09/03/2015
ICD: An ApplicationConclusions • Fortheexamplesshown, ICD seemstobeat least asgood a methodas CL • ICD outperforms CL if large claimswithunusualpatternsareincluded in claimshistory • Performance does not seemtodepend on volume • Nooutperformanceifclaimshistorycontainssignificantcalendaryeareffects (changes in legal environment, inflation) orchanges in claimshandlingspeed Individual Claim Development - Bas Lodder, 09/03/2015
Micro-Level ReservingWhy (not)? • Deterministic ICD canperform well ifclaimsdata do not containcalendareffects • Challenges • IBNYR claimsneedtobeestimatedseparately – comparisonwith CL onlypossible after removing IBNYR claims • a large amountof individual claimsdataneedstobeprocessed IT / actuarialtools • the model presentedprovides a bestestimate, errorestimatescanbederivedas well • Likeanyclaimsreservingmethod, ICD requiresactuarialjudgement! • ensuringhomogeneity in claimshistory • parameterchoice / model options • sensitivitytesting – robustness! • understandingdifferencesto CL andothermodels • Outlook: stochastic ICD • moresuitable in caseofchangingclaimshandlingspeed • canprovide a distributionofultimateclaimamounts Individual Claim Development - Bas Lodder, 09/03/2015
ICD: An ApplicationFurther questions ? Individual Claim Development - Bas Lodder, 09/03/2015
Dessert: Personal Liability (0.1 MCHF – 5 MCHF)Incurreddata(300 claims) • Thisdatasetcontainssome large all-or-nothingclaims, mostly in earlier AYs • In CL, such claimsaffectage-to-agefactors, causinglowestimates • In ICD, such claims will obtainnegligibleweights • The overall negative deviationis due to a combinationof • conservativeclaimreserves • fastersettlementofclaimsover time Individual Claim Development - Bas Lodder, 09/03/2015