Erling Eide: Rettsøkonomi, 4. avd. Del 3 Erstatningsrett Hovedtema: Analyser av virkninger av grunnvilkår Drøftelser av ønskeligheten av forskjellige grunnvilkår Grunnleggende modell (ensidig skademodell) Virkninger av skadevolders valg av aktsomhet ved forskjellige ansvarsregler Hvilke regler gir samfunnsøkonomisk ønskelig aktsomhet? Dvs aktsomhet der summen av aktsomhets- og skadekostnader er minst Bidrar skjønnsmomenter til slik aktsomhet? Utvidelser Aktivitetsnivå og aktsomhetsnivå (behandles kort) Simultant valg av aktsomhet (behandles ikke) Sekvensielt valg av aktsomhet (behandles ikke) _____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

8 Grunnleggende modell av skadeforvoldelse og ansvar 8.1 Forutsetninger Skadevolders aktsomhetsnivå (x) påvirker sannsynligheten (P) for skade Skadelidte kan ikke påvirke sannsynligheten for skade Aktivitetsnivået antas gitt (konstant) Ulykkeskostnader = aktsomhetskostnader + skadekostnader Samfunnsøkonomisk ønskelig aktsomhet: den som minimaliserer summen av kostnader Ingen forsikringsmuligheter 8.2 Sammenhenger i modellen og presiseringer Aktsomhetskostnader proporsjonale med aktsomhet: cx Forventet skadekostnad: P(x)S P er sannsynligheten for skade P avtar med økende aktsomhet x S er skadens omfang (i kr.) Kurvens form: Når x er liten, vil et tillegg i x gi en sterk reduksjon i P Totale ulykkeskostnader: cx + P(x)S _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

8.3 Samfunnsøkonomisk ønskelig aktsomhet Bestemmes ved bruk av minstekostnadsprinsippet: Den aktsomhet som gir de laveste totale kostnader: Min P(x)S + cx, som gir x* Kostnader Totale kostnader, P(x)S + cx Aktsomhetskostnader, cx _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Forventede skadekostnader, P(x)S x* Aktsomhetsgrad, x Figur 8.1 Aktsomhetskostnader, forventet skade og totale ulykkeskostnader: Optimal aktsomhet

8.4 Analyse av grunnvilkårene Totale kostnader, P(x)S + cx Aktsomhetskostnader, cx Skadekostnader, P(x)S x* Aktsomhetsgrad, x Figur 8.2 Skadevolders kostnader ved objektivt ansvar (uthevet) 8.4 Analyse av grunnvilkårene (i) Hva er best for samfunnet? (Betinget normativt spørsmål) Se pkt. 8.3 (ii) Hva skjer? Hva vil aktørene gjøre? (Positivt spørsmål) Ad (ii): Forutsetter rasjonell adferd: Målsetning: Minimalisering av egne forventede kostnader Betingelse: Aktørene kjenner: c, P(x), S, og ansvarsregler Valg: Aktsomhetsnivå 8.4.1 Ikke erstatningsansvar Valg: x = 0 8.4.2 Objektivt ansvar (fig. 8.2) Valg: x = x* Skadevolder velger i egeninteresse det samfunnsøkonomisk optimale ______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

8.4.3 Culpa 8.4.3.1 Nærmere om culpaansvaret Culpanorm: x! Rasjonell adferd: x = x! Fig. 8.3: x! = x* 8.4.3.1 Nærmere om culpaansvaret (i) Er modellen en god beskrivelse, representasjon, av culpaansvaret? (Positivt spm.) (ii) Hvordan bør culpaansvaret være for å gi x*? (Betinget normativt spm.) Ad (i): Sammenheng mellom forventede skadekostnader og skjønnsmomenter? aktsomhetskostnader og skjønnsmomenter? Avspeiler kostnadsminimalisering den rettslige avveining av skjønnsmomenter? Kostnader Totale kostnader, P(x)S + cx ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Aktsomhetskostnader, cx Skadekostnader, P(x)S x! Aktsomhetsgrad, x Figur 8.3 Skadevolders kostnader ved culparegel, x! = x*

8.4.3.1 (forts.) Er skjønnsmomentene egnet til å bestemme optimal aktsomhet? - Er skjønnsmomenter et annet navn på kostnadskomponenter? - Kan skjønnsmomenter transformeres til kostnadskomponenter? - Har RØ et mer presist begrepsapparat og en bedre analysemetode? 8.4.3.2 Skjønnsmomenter og kostnader 8.4.3.2.1 Autoritetenes skjønnsmomenter ______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

8.4.3.2.2 Skjønnsmomenter ved fastsettelse av culpanormen, og skadekostnader (a) Hensynet til forventet skadekostnad Hagstrøm: - Jo høyere forventet skade, desto lettere kan skadevolder bli ansvarlig Lødrup og Nygaard: - Andre ord, men god korrespondanse Kostnader kr. Aktsomhetskostnader, Forventet skadekostnad (høy) _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Forventet skadekostnad (lav) x*lav x*høy Aktsomhetsgrad Fig. 8.4 Hensynet til forventede skadekostnader

8.4.3.2.2. (forts.) (b) Hensynet til aktsomhetskostnader Hagstrøm: Oppdagelsesmuligheten (mht risikoen) Retningslinje: Jo enklere oppdagelsesmuligheter, desto mindre skal til for ansvar - Oppdagelsesmuligheten kan bedres ved anskaffelse av måleinstrumenter, opplæring … - Tiltakene koster - Tiltakene kan transformeres til kostnadskomponenter (aktsomhetskostnader) Forventet skadekostnad Aktsomhetskostnader, lave Aktsomhetsgrad x*lav x*høy Kostnader kr. Aktsomhetskostnader, høye _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Fig. 8.5 Hensynet til aktsomhetskostnader Ad billigere tiltak: Retningslinje: Jo lavere aktsomhetskostnad, desto mindre skal til for ansvar Konklusjon: Retningslinjer leder i retning av optimal aktsomhet

8.4.3.2.2 (forts.) (c) Avvergingsmuligheten (mht skaden) Juridisk retningslinje (vedr. tidspress) Jo større tidspress, desto mer skal til for å komme i ansvar Avvergingstiltak: Rensetiltak, varsling av potensielle skadelidte og innhenting av ekspertråd Avvergingstiltak koster: Jo større tidspress, desto dyrere blir rensetiltakene Jo større tidspress, desto dyrere blir varsling Jo større tidspress, desto dyrere blir ekspertene 8.4.3.2.3 Er avveiningen av momenter egnet til å identifisere optimal aktsomhet? Learned Hand (Federal Judge): Uaktsomhet hvis K < PS, der K = kostnaden ved å unngå skade P = sannsynligheten for skade S = skadens omfang Ussing (Skyld og Skade, 1914): Omtrent som Learned Hand Rudimentær nytte-kostnadsanalyse (K-H-effektivitet) ikke uvanlig i jus Forskjell mellom LHs og ulykkesmodellens aktsomhetskriterium LHs/Ussings kriterium: Basert på totale kostnader Ulykkesmodellens kriterium: Basert på marginale kostnader Konklusjon: Kravet til optimal aktsomhet stemmer med rettstradisjon og med juridisk argumentasjon. Mer presis? ____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

8.5 Utvidelser av skade- og ansvarsmodellen 8.5.1 Aktivitetsnivå: z Forutsetninger: (i) S (skade) er proporsjonal med z (som ikke kan observeres av retten) (ii) Jo høyere aktivitetsnivå, desto høyere inntekt (ekskl. aktsomhetskostnader) (iii) Avtagende marginal nettoinntekt Samfunnsøkonomisk ønskelig adferd: - Ønskelig aktsomhetsnivå: x* - Ønskelig aktivitetsnivå: z* Ansvarsregler: Ikke ansvar: Lav x og høy z Objektivt ansvar: x* og z* (Best?) Culpa: Hvis normen settes til x*, vil z bli for høy Marginal inntekt Kostnader _________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________ Marginal nettoinntekt Marginale forventede skadekostnader, P(x*)S Fig. 6.6 Bestemmelse av optimalt aktivitetsnivå (for gitt aktsomhetsnivå x*) 1 2 z* Aktivitetsnivå (timer) pr. dag (uke)

8.5 Utvidelser av skade- og ansvarsmodellen (forts.) 8.5.2 Skadelidtes forhold Simultant og sekvensielt valg av aktsomhet