Crimes feature so often in the daily news that it is easy to get the impression society is becoming increasingly violent and unsafe. Even when annual crime figures suggest otherwise - as they did yesterday, for the third year in succession - there is a tendency to suppose the statistics are at best a temporary reversal of a remorseless trend.
But three years of improvement becomes hard to deny. Unbelievable it may be to those who do not want to believe it, but our systems of law enforcement are doing something right.
Naturally Police Minister Anne Tolley is keen to attribute the improvement to an increase in "frontline" police and changes that mean they are more visible in communities and they are putting efforts into crime prevention as well as detection and arrests. She is no doubt right, though wrong to imply these are initiatives of her Government.
The previous Labour Government was just as committed to increasing police numbers and improving their community presence. The truth is, governments of all stripes endorse the policies the police professionals believe will work, and it is the professionals who deserve the credit.
It is a pity, therefore, that they are not more candid about what changes, if any, they have made that explain the new trend. Releasing the figures for last year, Acting Commissioner Viv Rickard yesterday said only that they were delighted, that the result would be a great encouragement and motivation for staff and that the figures suggested fewer people were experiencing crime.
Yet by his own account the 376,013 reported offences last year, a 7.4 per cent drop on 2011, was the lowest figure in 24 years. That is a generation ago. On that scale, the turnaround in recent years is remarkable and it is important that the reasons are studied and clearly agreed.
As always, the police figures are "reported offences"; they can not include crime that, for various reasons, might not be referred to the police.
Some categories of crime, such as sexual offending, have always been under-reported, and others, burglary, for example, may seem no longer worth reporting if police resources are stretched.
But slightly more sexual offences were reported last year, while burglary was not the only category to decline. Serious assaults, which are readily reported, also dropped. In any case, a declining trend in reported offences should not be denigrated. It probably reflects a decline in unreported crime, too. It is fair to conclude that society is more law-abiding and safer than it used to be.
It is particularly gratifying that the trend is shared in communities of disparate wealth. While the largest drop (12.4 per cent) was recorded in the Waitemata police district, Auckland City (12.1) and Counties Manukau (11) were close behind.
Canterbury bucked the trend but only because criminal activity there returned to more normal levels after becoming very low in the period of the earthquakes. Those who look for the hole in every doughnut can highlight the Canterbury figure, and note that while while homicides nationally dropped by 15, the number found to have been murdered rose by 3 last year to 42.
Critics can also concentrate on the police admission that they resolved only 47 per cent of crimes reported, the same level as the previous year. That suggests the reduction in offending cannot be attributed to "tough" measures such as harsher penalties and a greater likelihood of being caught. It rather reinforces the suggestion that community policing has made the difference.
Police who knew their community, knew which youngsters were at risk of committing crime and intervened effectively, have probably made the difference. It is good news.