There may be lies, damned lies and statistics — but when it comes to casualty data, there are also "alternative" facts.

Nordic Association of Marine Insurers (Cefor) actuary Astrid Seltmann has cautioned aficionados of marine claims statistics to be aware of terminology, as "alternative" facts are available from different sources.

The insurance market considers a major claim to be an extraordinarily expensive casualty costing more than $5m. But commercial data providers report serious casualties that are not necessarily that costly.

Serious casualties are defined by the nature of the mishap, rather than the financial outcome. So major claims are normally the result of serious casualties — but serious casualties do not necessarily equate to major claims.

Seltmann highlighted the alternative facts of casualty reporting in a recent International Union of Marine Insurance (IUMI) presentation to the International Maritime Organization (IMO)'s maritime safety committee, and returned to the issue in Cefor’s half-year report on the state of the hull market.

She told the IMO committee that Lloyd’s List Intelligence was reporting a strong increase in "serious" casualties in 2016, while Cefor’s Nordic Marine Insurance Statistics (NoMIS) database showed little in the way of major claims.

This is not a small statistical discrepancy but two widely quoted sources reporting polar opposite trends. So who’s right?

Seltmann’s answer is that both are, within the limits set by differing definitions.

Cefor’s half-year report cautions that the terminology used to report casualties can produce considerable discrepancies between different organisations. Seltmann compared the NoMIS database with the Lloyd’s List Intelligence one and was able to match about 7% of the former’s claims.

Most claims marked as "serious" by Lloyd’s List Intelligence were not "major" losses in insurance industry terms. Less than 40% of its "serious" casualties had a cost of more than $1m, only 13% exceeded $5m and just 6% went above $10m.

According to an IMO definition, serious casualties can be a breakdown necessitating a tow — although there can also be “very serious” casualties, involving loss of a ship or life, or severe pollution.

For total losses, fortunately there is agreement that this is a vessel sinking, with a constructive total loss being a ship damaged beyond economically feasible repair, taken to be 80% of the insured value of a vessel, under the Nordic Insurance Plan.

The data from Cefor and NoMIS, along with the "T" Code loss information from the Lloyd’s market, is derived from real-world claims. But commercial databases do not have such sources, so they compile their statistics from a miscellany of sources and are not based on actual claims.

Historically, the Institute of London Underwriters (ILU), which represented more than 100 insurance ventures writing marine business, gathered casualty information but membership had dropped to just 41 companies by the time it went out of business in 1998.

The Salvage Association, a joint venture of the Lloyd's market and ILU companies, was also an important provider of casualty reports but ceased making its information publicly available in 1994. The association was acquired by British Maritime Technology in 2001 and, since 2011, has been part of Braemar Shipping Services, which is a shipbroking and surveying group, so its fundamental nature has changed.

Individual insurers with a major commitment to loss prevention, such as the Swedish Club, issue reports on their own claims experience, mainly with a focus on helping members and other insureds minimise claims. And casualties sufficiently costly to be pooled by the International Group of protection-and-indemnity (P&I) clubs are reported by TradeWinds.

For the past five years, big German insurance group Allianz has issued an annual Safety and Shipping Review. However, the ship losses and statistics are not drawn from its own underwriting or other insurance industry sources but are based on third-party reports.

Apart from NoMIS and the T Code statistics from the Lloyd’s market, information about claims trends and casualties comes mostly from non-systematic sources such as reports on the Internet and social media, and in local newspapers.

Over recent years, there has also been a notable growth of hobbyist and other small websites reporting ship information, including casualties, but often of modestly size craft that may be river boats, of timber construction, fishing vessels or those with no IMO numbers.

It seems unlikely that major tanker spills or the loss of large bulkers or containerships go unnoticed but other issues are raised by a haphazard gathering of information.

Groundings, for example — mostly hard-to-hide events that may well occur in sight of the shore — are more likely to be reported than machinery damage incidents that never come to light.

But many reported groundings seem to involve little or no damage and are often resolved within a few hours, whereas more serious, less visible events escape scrutiny.

However, machinery damage is one of the biggest sources of costly claims, so differences in reporting matter.

The Swedish Club reported last year that more than half of its hull claims arose from machinery damage, compared with less than 10% for groundings. In terms of cost, the machinery category exceeded 30% and groundings were less than 14%.