report

The Civil Standard of Proof -What is it, actually?

Grop member: Yin Wang Jialin Hu

Jinghan Lu Jin Zhang

1. Introduction

The standard used in criminal cases is higher than that used in civil cases for Common law.

The standard used in criminal cases is same as that used

in civil cases for Continental European Civil Law.

What is Preponderance of the Evidence in US Law?(Common Law)

•“To ‘establish by a preponderance of the evidence’ means to prove that something is more likely so than not so. In other words, a preponderance of the evidence in the case means such evidence as, when considered and compared with that opposed to it, has more convincing force, and produces in your minds belief that what is sought to be proved is more likely true than not true. This rule does not, of course, require proof to an absolute certainty, since proof to an absolute certainty is seldom possible in any case.”

- explained in the Federal Jury Practice and Instructions

How about English Law?(Common Law) - Lord Denning provided a definition named “balance of

probabilities” in Miller vs. Minister of Pensions, which is the most cited paraphrase.(civil matters)

- “If the evidence is such that the tribunal can say ‘we think it more probable than not’ then the burden is discharged, but if the probabilities are equal it is not.”(civil matters)

- The jury must be convinced beyond any reasonable doubt that the facts alleged by the prosecution are true in a criminal cases.

- state of mind of the fact finder (“convinced beyond reasonable doubt”)

-decision threshold: well above 50%

- evidence or probabilities (“objectively”) - preponderance of evidence - decision threshold: greater and equal to 50%

Standard of Proof (Common Law)

The difference between the criminal and civil standard of proof lies in the degree of belief (or conviction) required for finding for the party bearing the burden of proof. This degree of belief is much higher in criminal cases than it is in civil cases.

Continental European Civil Law ● No gerenal difference between standards of proof for civil

and criminal matters ● Standard of proof is always the full conviction(near

certainty) ● “a court must be convinced of the truth of a factual

allegation based on objective grounds. Absolute certainty is not required. It is sufficient if the court has no serious doubt or any remaining doubt appears insubstantial.” - Swiss Federal Supreme Court

● decision threshold: above 90%

Civil Law vs. Common Law in civil cases ● Less people dispute that the degree of

conviction required for finding for the plaintiff in Civil Law is much higher than that required by the Common Law’s “preponderance of the evidence” or “balance of probabilities” standard.

● The scholarly debate is further evidence that, at least in theory, the civil standard of proof in Germany (Civil Law) is indeed (much) higher than in US or English law.(Common Law)

● The insistence of Civil Law that the standard of proof in civil cases is “full conviction”, meaning “near certainty” has left Common Law lawyers puzzled.

● Kevin M. Clermont and Emily Sherwin criticize that civilians are wrong in a strongly worded article.

● They came to the conclusion that Civil Law values the perceived legitimacy of the court system higher than a rational approach to judicial decision making.

Standard of proof in Swiss(Continental Civil Law)

● When asked directly, the members of court express a high decision standard in line with case law. But when Swiss judges are asked to estimate the error costs associated with each outcome and the error-cost- minimizing decision threshold is calculated based on the responses, the resulting standard is lower than when asked directly.

● There is a 50% probability that a request in a civil action will be granted when the judge is convinced only to a degree of 63% that the factual allegations supporting the claim are true.

2. Measuring standards of proof

Direct rating or self-report method

It is useful for assessing whether different verbal definitions of the standard of proof are actually perceived as requiring different subjective probabilities of guilt for a conviction.

The problem with using this approach with sophisticated subjects such as judges is that the judges know the theoretically required standard of proof, and they will likely give the answer that is expected and not the threshold actually used.

● The problem with the decision theory-based method is that it only allows the estimation of a normative decision threshold.

Decision theory-based method Pr(p) is the probability that the plaintiff’s (or prosecution’s)

allegations are true.

The expected costs are minimized when Pr(p) meets or exceeds

the value calculated according to the above equation.

Dfp is the disutility of a false positive decision.

Dfn is the disutility of a false negative.

Dcp is the disutility of a correct positive.

Dcn is the disutility of a correct negative.

Parallel-ranking method ● It was originally developed for an in-between subject design. Half the subjects express

their belief in the guilt of the accused as a subjective probability, the other half only makes a dichotomous guilty-innocent verdict judgment.

● The subjective probabilities are ranked from highest to lowest, and the minimum threshold for a guilty verdict is determined by counting down the probability ratings to the rank number corresponding to the proportion of guilty verdicts obtained in the dichotomous decision condition.

● The in-between subjects design has the disadvantage of low statistical power. A within-subject design on the other hand is problematic because in some studies, order effects were found.

● This study uses a within-subject design, but varies the order of judgment and rating to be able to control for order effects. The decision threshold is estimated using a binary logistic regression with the guilty verdict as dependent variable and the expressed subjective probability as independent variable. ○ The advantage of this method is that it estimates the degree of belief actually

required for a probability of x% that the subject will grant the claim, which is the parameter of interest.

3. Loss aversion and standard of proof in civil cases

Loss aversion ● People are risk-averse when choosing between a sure gain and a positive

gamble, but risk- seeking when choosing between a sure loss or a negative gamble.

● Kahneman and Tversky’s Prospect Theory, posits an S-shaped value function that is concave in the domain of gains and convex in the domain of losses. And they also found that losses loom larger than gains.

● The ratio of G/L that makes an even chance to gain G or lose L just acceptable lies between about 2 and 2.5 for both risky and riskless choice involving monetary outcomes and consumption goods. This means that people experience about twice the disutility for a loss than they experience utility for a corresponding gain.

Reference-dependent valuation and civil litigation ● The plaintiff frames the outcome of the litigation as a gain compared to the

status quo ante trial. The defendant sees the outcome as a loss. ● In an overwhelming majority of cases, the plaintiff can asks the court to

impose a change of the status quo. ○ e.g., make the defendant pay, turn over possession of a good or stop

behaving in a certain way ● In all of these cases, the losing defendant will conceive compliance with

the judgment as a loss.

● Zamir and Ritov have hypothesized that loss aversion may also influence the decision threshold of the judge in a civil case. ○ This requires the judge – who does not himself or herself gain or lose

anything from his or her decision – vicariously experiences the gain or loss of the parties. ■ The judges may influenced by the party’s perspective despite

having nothing at stake themselves. ■ Judges are more likely to recommend settlement to a plaintiff

than to a defendant, thereby showing the same pattern of risk aversion that the parties themselves show.

Hypotheses to be tested ● This hypothesis is tested using a logistic regression with the decision

threshold as dependent variable. ○ If loss aversion had an influence on the required threshold for granting the

plaintiff’s request in a civil action, then those individuals with a higher G/L ratio, or a stronger loss aversion, should have a higher decision threshold. While on average the G/L ratio is about 2, there is considerable heterogeneity in loss aversion.

● Using the G/L ratio as a predictor for the decision threshold in a logistic regression to test the hypothesis regarding the influence of loss aversion on the decision threshold in civil cases.

Measuring loss aversion This was done using a simple choice between a six lotteries.

v(x) is the utility of the outcome x ∈ {G, L}, λrisky denotes the coefficient of loss aversion in the risky choice task; and w+(0.5) and w–(0.5) denote the probability weights for the 0.5-chance of gaining G or losing L, respectively.

● A decision maker will be indifferent between accepting and rejecting the lottery if w+(0.5)v(G) = w–(0.5)λriskyv(L)，where L denotes the loss in a given lottery and G the gain;

● If we assume w+ = w– as proposed by Prelec, only the ratio v(G)/v(L) = λrisky defines the implied loss aversion in the lottery choice task. assume (v(x) = x), then λrisky = G/L. ○ i.e., an individual that declines to play any of the lotteries has an

implied loss aversion of > 3; an individual that accepts the first lottery and declines all the others one of 3 and so forth. Someone who accepts all the lotteries exhibits a loss affection of ≤ 0.87.

4. Method and paticipants

A. Online Questionnaire

How does it work?

Binary Logistic Regression

At the center of the logistic regression analysis is the task estimating the log odds of an event. Mathematically, logistic regression estimates a multiple linear regression function defined as:

B. Paper Questionnaire

For the estimation of the error costs associated with each outcome of a civil action

5. RESULT

A. Result from the direct rating/self-report method

● 118 (73.8%) court members identified the correct verbal definition of the default standard of proof of “full conviction”.

● 40 (25%) chose the verbal definition of the intermediate standard of “high probability”

● 2(1.2%) court members chose the definition of “prima facie evidence”.

● 19 participants indicated that a 100% certainty was required under the standard of full conviction

● the lowest threshold indicated was 51% ● The median decision threshold under the standard of

full conviction was 91%

B. Results from the decision theory-based method

The modal answer, given by 34 (72%) of the participants, was to invest CHF 50,000 each in the

prevention of a false positive (upper right cell in Table 3) and a false negative (lower left cell in Table

3) and nothing in the prevention of the correct decisions. The second most common answer, given by

3 participants, was to invest CHF 25,000 in the prevention of each outcome.

● 10 (21%) participants have invested different amounts in the prevention of the two types of errors.

● Seven of those invested more in the prevention of a false positive (grant of request despite no loan given) than in the prevention of a false

negative (denial of request although loan was given).

● The decision thresholds resulting from equation (1) using the implied error costs indicated by these seven participants result with a single

exception in thresholds below 63%.

● The implied error costs of just one participant result in a decision threshold of 87.5%, close to the mean threshold obtained with the direct

rating method.

C. Results from the binary logistic regression

The first four columns report the results for the “action” condition, the last four columns those for the

“negative declaratory action” condition (since the order of questions did not have an effect, as will be shown

below, the results are pooled across the “order” condition).

the probability of grant increases with an increase in the conviction that the allegations supporting the claim are true. The order of questions and membership of court do not exert a significant influence, but the type of request does, with the negative declaratory action being granted at a much lower rate.

Figure 2 plots the function of degree of belief on probability of grant for both types of claims. The grey shaded areas indicate the 95%-confidence intervals, estimated by bootstrapping.81 Since few participants granted the negative declaratory action, the confidence intervals for the negative declaratory action are much wider than for the action.

5 (3%) of the court members and 41 (18%) of the general population sample showed non-monotonic valuations which leaves 337 observations (152 members of court and 185 members of the general population).

The interaction of loss aversion and type of request is significant. With increasing loss aversion, the probability of grant of the request in the action condition (order of payment) decreases.

6. Discussion

Decision threshold is about 90%

What does it mean?

Age vs. the degree of belief

The probability of convicting an accused in a criminal trial increases with the age, but the effect of age in the civil case goes in the opposite direction. ie. the higher the age, the lower the probability of grant.

Individual’s Loss Aversion Influences vs. Decision Threshold

a higher loss aversion leads to a higher decision threshold

ie.The plaintiff whose car has been damaged by the negligent driving of the defendant may well experience the award of damages by the court as a gain, and the defendant as a loss, from the baseline “damaged car”

Conclusion The results suggest that the standard of proof actually employed by Swiss judges is not much different from the Common Law’s “preponderance of the evidence” standard, despite the doctrinal insistence to the contrary.

The error costs the Swiss judges and judicial clerks associate with each possible outcome of a civil action imply an error-cost-minimizing decision threshold of just 51%, the same as the threshold usually stated for the Common Law’s standard of proof. Also,with individuals exhibiting stronger loss aversion having a higher decision threshold.

Reference Schweizer, Mark. “The Civil Standard of Proof – What Is It, Actually?”

SSRN Electronic Journal, Dec. 2013, doi:10.2139/ssrn.2311210. https://www.coll.mpg.de/pdf_dat/2013_12online.pdf

LaMance, Ken. “Preponderance of the Evidence vs. Beyond a Reasonable Doubt.” Attempted Murder Lawyers | LegalMatch Law Library, 19 Dec. 2018, www.legalmatch.com/law-library/article/preponderance-of-the-evidence-vs-bey ond-a-reasonable-doubt.html.