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Investigation of Causative Factors Associated with Summertime Workplace Fatalities

identification of contributing factors to summertime fatalities

Overview

The work reported in the section 'Results of detailed data analysis' has identified various seasonal trends of workplace fatalities in relation to industrial sectors, regions, employee ages and employment status. The work reported in this section concerns the identification of factors which are associated with, or have a contributory effect on, the occurrence of the seasonal changes in workplace fatalities. Some of these factors have been identified in the previous analyses using the data directly recorded along with the fatality investigation, such as the type of industry and the employees' age. However, for either technical or practical reasons, a great deal of potentially useful information cannot be recorded in the fatalities database, such as detailed weather conditions at the time when the incident happened, and any sociological background information around the fatalities. Those factors might have played some contributing roles in the occurrence of the fatal incidents. This section aims to identify a wider range of potentially contributory factors including workplace factors, environmental factors, sociological factors, and personal or individual factors, and to assess the extent to which they may have contributed to the incidents recorded in the fatalities database.

Workplace Factors

Workplace factors and task specific/operational factors are very often the most relevant to workplace fatalities. The development of effective preventive measures to reduce the incidence of seasonal workplace fatalities arising from workplace/operational factors should be a priority for the Department if it is to achieve its goal of workplace safety.

The workplace factors that were identified and analysed were obtained mainly from two primary information sources: workplace fatality investigation reports and interviews with ISEs (Industry Safety Experts).

Analysis of workplace fatality investigation reports

Of the total 362 workplace fatal incidents from 2000 to 2005, 299 full investigation reports were available for detailed review by the project team. Each of these reports were read/analysed by the research team and relevant information was extracted.

In those workplace fatality investigation reports, the 'direct causes' of death were recorded by the investigators. These have since been classified. For example, whether the death was due to 'drowning' or 'fall from height'. This information provides good insight into 'what happened', but gives little information of 'why it happened'. These 'direct causes' were captured by the research team during the course of the report analysis. Figure 27 below summarises the results. Vehicle rollovers caused nearly one quarter of all fatal work related deaths during 2000 to 2005. Vehicular related fatal incidents are discussed further in the section entitled 'Workplace factors'.

Figure 27: Primary causes of death or fatal injuries for the incidents investigated

Figure 27: Primary causes of death or fatal injuries for the incidents investigated

Data table for Figure 27

(299 between 2000 and 2005)

In order to gain further insight into what caused each of the fatalities, each of the incident reports were reviewed and categorised according to the contributory factors that led directly to the incident occurring. While the categorisation of incidents relied entirely on the interpretation of the information recorded by investigators it provides important direction on the types of preventative strategies that should be considered.

One or more contributory factors were recorded for each incident. The majority of fatalities were associated with multiple (e.g. 2 or 3) contributory factors. Figure 28 lists each contributory factor and the percentage of workplace fatalities associated with it. The data show that "Human Error" contributed to at least 43% of the fatalities recorded and that "Procedural Violation" contributed to at least 27% of the fatalities recorded. In addition, in 16% of cases, a behaviour occurred that may have been either a procedural violation or human error[14]. The vast majority of human errors or violations can be prevented by improved equipment or workplace systems design. In 22% of the fatalities reported, a failure in design could be recognised, either by the investigator at the time or during subsequent review of the incident report.

Figure 28: Contributing factors as identified by the investigators

Figure 28: Contributing factors as identified by the investigators.

Data table for Figure 28

(299 workplace fatality investigation reports from 2000 to 2005. Please note that there are multiple counts for the contributing factors because each incident almost always involved more than one factors)

Figure 29: Vehicular statistics

Figure 29: Vehicular statistics.

Data table for Figure 29

Figure 29 shows that, of all the fatal incidents during 2000 to 2005 in the Department of Labour's database 52% involved vehicles. Of those, approximately 1/3 of the fatalities occurred to a person who was not driving a moving vehicle at the time. Where the fatality occurred to a person in or driving a moving vehicle, the fatality reports indicate that wearing a seatbelt or helmet could have prevented the fatality in up to 33% of cases (nearly 8% of all fatalities).

Interviews of Industry Safety Experts

For the identification of a wider range of workplace factors for different industries, the experts' assessments that were obtained from the ISE consultation (described in the Literature review) were used for the analysis. The focus of this exercise was to look into those seasonal related factors in or surrounding the workplace, which have not been covered by the investigators. The following workplace factors were investigated in this process:

The workplace factors were analysed for their possible association with the occurrences of workplace fatalities. Correlation coefficients were calculated between the expert ratings on the seasonal changes of the workplace factors for different industries, and the occurrence of workplace fatalities during the corresponding seasons for the corresponding industries.

ISE rating data were only available for the following top-level ANZSIC industries and the sub-sectors shown:

Table 2 shows the results of correlation analysis between those workplace factors that have been quantified for their seasonal changes (by expert ratings) and workplace fatalities for different industrial sectors. The table includes only the factors which have been found to be significantly associated with seasonal workplace fatalities corresponding to at least one or more industries. These results are based on the workplace fatality data and the ISE rating scores, and are independent of the findings that have been obtained by using other analytical methods such as the analysis of workplace fatality investigation reports.

Table 2a: Correlation coefficients between some workplace factors and workplace fatalities for different industries

Factors Overall fatalities Agriculture, Forestry & Fishing Horticulture & fruit growing
Hours worked per day 0.66* 0.70* (ISE ratings on dairy & cattle farming) NS
Level of staffing 0.63* 0.30* 0.75*
Level of casual labour 0.60*Ratings on construction 0.28* 0.76*
Visitors/non-workers attending work sites 0.59*Ratings on construction NS 0.74*
Variation in work activities NS 0.28* NS
Work involving vehicles NS NS 0.71*
Work under poor weather conditions -0.69*Ratings on construction NS NS
Lack of recovery from fatigue 0.60*Ratings on agriculture 0.33** NS
Tight timescales / deadlines NS NS 0.75*
Use of hazardous substances 0.58*Ratings on construction NS NS

Table 2b: Correlation coefficients between some workplace factors and workplace fatalities for different industries

Factors Overall fatalities Construction Manufacturing
Hours worked per day 0.66* NS NS
Level of staffing 0.63* NS NS
Level of casual labour 0.60*Ratings on construction NS NS
Visitors/non-workers attending work sites 0.59*Ratings on construction NS 0.64*
Variation in work activities NS -0.41* NS
Work involving vehicles NS -0.34* NS
Work under poor weather conditions -0.69*Ratings on construction NS NS
Lack of recovery from fatigue 0.60*Ratings on agriculture 0.33* NS
Tight timescales / deadlines NS NS NS
Use of hazardous substances 0.58*Ratings on construction NS NS

 

Note: * statistically significant at p≤0.05 level; ** p≤0.01. NS: not significant (p>0.05).

The correlation coefficients indicate a statistical association between the occurrence of workplace fatalities and some workplace factors that have been rated by the ISEs for seasonal variations. A positive correlation indicates that an increase in the workplace factor is related to an increase in the occurrence of workplace fatalities. For example, 'Hours worked per day' (which generally goes up in summer and down in winter) is positively correlated with the occurrence of workplace fatalities in all industries, which means that more hours worked per day are related to more work-related fatal incidents. A negative correlation would suggest that a change in the workplace factor towards a certain direction (either increase or decrease) is associated with a change in the work-related fatalities in the opposite direction. For example, in the 'Construction' sector 'Work involving vehicles' is negatively correlated with the work-related fatal incidents, suggesting that more vehicle use at work (e.g., prepare the work site and building materials before the building work takes place) is related to fewer fatal incidents (possibly due to reduced chance of falling from height). The meanings of all these correlation results are summarised and described in Table 5, and some relevant issues will be discussed in the detailed discussion of Workplace factors.

Initially, the results indicate that several workplace factors are significantly associated with the occurrence of workplace fatalities in some industrial sectors. 'Level of casual labour', for example, is positively associated with workplace fatalities in the agriculture industry, and with its sub-sector 'Horticulture & fruit growing', suggesting that increased casual labour is related to a higher rate of workplace incidents. This finding is in line with the fact that there is an increased labour demand in the horticulture industry during the summer and through to autumn seasons to cope with crop harvesting (February-May)[15] (with reference to Figure 12).

A highly significant correlation was also found between 'Average Weekly Paid Hours[16] and the workplace fatality data for all industries (r=0.54, p≤0.001), suggesting that longer work hours in summer could also be a contributing factor to the increase in workplace fatalities.

It needs to be understood that the correlation analysis can only tell which factors are strongly (to a level of significance) associated with the occurrence of an event (in this case, workplace fatalities), thus they may have played a contributory role in the incidents. However, this does not necessarily mean that these factors have actually caused or contributed to those incidents. For example, while the pattern of ice cream sales may correlate with the pattern of workplace fatalities there is not necessarily a causal relationship between the two. The causal effects of these factors will need to be interpreted in connection with a wide range of multiple factors, including the environmental conditions, the sociological conditions, the individuals involved, as well as the actual work activities.

Environmental Factors

Various types of environmental factors have been investigated for their possible association with the occurrence of workplace fatalities. A wide range of environmental indicators were included in the analysis, such as temperature, rainfall, sunshine, humidity, fog, frost, snow, wind, gales, and so on.

Environmental data were provided by NIWA Climate Services at the request of the project team. The data were recorded by various weather stations across New Zealand on monthly basis from 2000 to 2005. In New Zealand, weather conditions vary between different regions during the same period of time. Therefore, it was necessary to analyse the environmental data with the fatality data on a regional basis. The environmental data were sorted according to the four regions as used in this study (i.e., Northern, Mid North, Central, and Southern). Correlation coefficients were calculated between the environmental data and the overall workplace fatality data for the same region over the same period.

Correlation analyses were also performed between the regional fatality data for each major industry with the relevant environmental data in a similar manner. Table 3 shows the results.

As mentioned earlier in the previous 'Workplace factors' the environmental factors that were found to significantly correlate with the occurrence of workplace fatalities suggest that these factors are associated with increased workplace fatalities, but they may or may not have played a direct contributory role.

Table 3a: Correlation coefficients between some environmental factors and workplace fatalities (2000-05)

Factors Overall fatalities Agriculture, Forestry & Fishing Construction
Mean monthly rainfall (mm) 0.29*** NS NS
Mean monthly wet days (rainfall ≥ 1mm) NS 0.71*** -0.20**
Mean monthly air temp (°C) 0.27** 0.60*** NS
Sunshine (hours) - 0.42*** NS
Ground frost (No. of days) NS -0.42*** NS
Fog NS NS NS
Snow NS NS NS
Mean speed of wind (km/h) NS NS NS
Gale (days) NS NS NS

Table 3b: Correlation coefficients between some environmental factors and workplace fatalities (2000-05)

Factors Overall fatalities Cultural, Recreational & Other Services Manufacturing Transport & Storage
Mean monthly rainfall (mm) 0.29*** -0.23** -0.22** -0.19*
Mean monthly wet days (rainfall ≥ 1mm) NS -0.23** -0.37*** NS
Mean monthly air temp (°C) 0.27** 0.40*** 0.50*** NS
Sunshine (hours) - 0.37*** 0.43*** 0.20**
Ground frost (No. of days) NS -0.35*** NS -0.35***
Fog NS NS NS NS
Snow NS NS NS NS
Mean speed of wind (km/h) NS NS 0.18* 0.21**
Gale (days) NS NS NS NS

 

Note: * statistically significant at p≤0.05 level; ** p≤0.01; *** p≤0.001; NS: not significant (p>0.05).

The correlation tests indicate a positive or negative association between some of the environmental factors and the occurrence of workplace fatalities. For example, 'wet days' are positively correlated with the workplace fatalities in the agriculture industry, suggesting that the more wet days, the more likely the incident occurrence in this sector (e.g. vehicle rollover on slippery ground). However, in the 'Construction' sector, wet days reduce the likelihood of a fatal incident (probably because less high risk external work is carried out). Thus the correlation is negative. The meanings of these results are described and summarised in Table 5, and some relevant issues will be discussed in detailed Discussion of 'Environmental factors'.

Sociological Factors

Various types of sociological factors have been analysed for their possible association with the occurrence of workplace fatalities. These factors were mainly based on the data published in Statistics New Zealand[17]. Other relevant data sources provided information on possible factors such as school holidays, public holidays[18], and daylight saving[19]. The following factors were analysed for their possible association with the occurrence of workplace fatalities:

Table 4 below summaries those sociological factors that were shown to be significantly associated with the occurrence of workplace fatalities for at least one industrial sector.

Table 4a: Correlation coefficients between some sociological factors and workplace fatalities (2000-05)

Factors Overall fatalities Agriculture, Forestry & Fishing Construction
Overseas tourist arrivals NS 0.31* 0.36*
Short-term arrivals-NZ residents NS NS 0.49*
School holidays NS 0.29* NS
Public holidays NS 0.29* NS
Daylight saving NS 0.28* NS
Household estimate (mean year ended) NS NS NS
Consumer Price Index (CPI) NS NS NS
Alcohol consu-mption-beer 0.41* 0.65*** NS
Total alcohol consu-mption NS 0.59** NS
Tobacco(tonnes) NS 0.42* NS

Table 4b: Correlation coefficients between some sociological factors and workplace fatalities (2000-05)

Factors Overall fatalities Cultural, Recreational & Other Services Manufacturing Transport & Storage
Overseas tourist arrivals NS 0.58* NS 0.57**
Short-term arrivals-NZ residents NS NS NS NS
School holidays NS NS 0.43* NS
Public holidays NS NS NS NS
Daylight saving NS NS NS NS
Household estimate (mean year ended) NS -0.53* NS NS
Consumer Price Index (CPI) NS -0.54* NS NS
Alcohol consu-mption-beer 0.41* NS NS NS
Total alcohol consu-mption NS NS NS NS
Tobacco(tonnes) NS NS NS NS

 

Note: * statistically significant at p≤0.05 level; ** p≤0.01; *** p≤0.001; NS: not significant (p>0.05).

Some sociological factors are found to be positively correlated with the occurrence of workplace fatalities, for example, people arriving from the overseas as tourists. The more tourist arrivals, the higher the work-related fatal incidents in some industries such as the agriculture sector. This may suggest that there is increased number of casual labourers during the tourist season. Casual labour has been regarded as an incident-contributing factor by other independent studies (summarised in Table 6). Increased tourists may also mean that there are more visitors/non-workers attending the work sites, another factor found to be related to the workplace fatalities (Table 2).

Another example is beer consumption, which is most significantly correlated with the workplace fatality data. However, as explained earlier, this does not necessarily mean that many work related fatal incidents were caused by beer drinking. This contributing factor will need to be considered in combination with other seasonal factors, and with other independent evidence. The meanings of these results are described and summarised in Table 5, with relevant discussions in the detailed Discussion of 'Sociological factors'.

Individual/Personal Factors

The analysis has looked into individual/personal factors of those involved in the workplace fatal incidents, such as their age, gender, employment status. Some of this information was recorded in the database and some was extracted from the workplace fatality investigation reports. This type of directly recorded information (and the detailed analysis as reported in the section' Seasonal Trend of the Workplace Fatalities') is considered to be more conclusive than the analysis of indirectly recorded data using correlation analysis.

Detailed analyses have previously shown that age is an important contributing factor, with those aged between 55 and 64 years being most likely to have fatal incidents in the summertime (p<0.05), and those between 35 and 44 years of age being most vulnerable during the autumn. In addition, the normalised data showed that older people (aged 65 and above) were found to have much higher fatality rate throughout the year as compared to other age groups, and they are particularly vulnerable during the autumn

As far as gender is concerned, of the 362 workplace fatalities that occurred from 2000 to 2005, 30 were female (8.3%), and 319 were male (88.1%)[20]. It is obvious that male workers are the major source of concern in relation to their involvement in the workplace fatalities. Further analysis using the normalised data showed a consistent result as obtained from the previous analysis (reported in section 3.2), indicating that the male workers aged between 55 and 64 had a higher rate of fatal incidents (3.69 per 100,000 workers per year) as compared to other age groups (45-54: 2.15; 35-44: 1.99; 25-34: 1.94; 15-24: 1.67) over the past six years (2000-05), apart from those aged over 65 who had the highest fatal incident rate (12.85), and most of them work in the agriculture sector.

For work employment status, 56.6% of the fatal incidents (205 out of 362 fatalities during 2000-05) were with those employed, followed by 23.2% (84 out of 362) of those self-employed, and 15.2% (55 out of 362) bystanders[21].

In summary, based on the data analysis using different methods and from different points of view, it has become evident that males working in agriculture industry, aged between 55 and 64, are most likely to have a fatal incident in their workplace during the summertime. This finding has been found to be conclusive and has been confirmed by different analysis and by statistical testing.

For the older workers aged 65 and over, although the results were not shown to be significant by statistical test, possibly due to the small data set available, their rate of involvement in the workplace fatalities was the highest among all age groups following data normalisation by worker populations. This result is indicative and can be used, in conjunction with other types of evidence, when developing safety strategies to tackle workplace fatal incidents.

Summary of Contributing Factors

Table 5 below summaries the contributing factors which have been identified in this chapter, using correlation analysis, it does therefore not include the contributing factors extracted from the fatality reports (see previous discussion on 'Workplace factors'). It must be noted that factors identified through correlation are not conclusive and they will need to be analysed/interpreted together with other factors as identified in other sources (e.g., incident investigation reports, ISE feedback), and with the support of independent evidence as reported in the next section.

Table 5 - Summary of contributing factors

Workplace factors
Factors Industries the factor is associated with Correlation coefficients & level of significance Note Description
Hours worked per day

All industries

0.66*

  

More hours worked per day are related to more workplace fatalities.

Agriculture - sub sector:

Dairy & cattle farming

0.70*

  

Longer work hours are associated with more fatalities particular in this sector.

Level of staffing

All industries

0.63*

Monthly data 00-05

Higher level of staffing is related to more fatalities.

Agriculture, Forestry & Fishing

0.30*

Monthly data 00-05

Agriculture -sub sector:

Horticulture & fruit growing

0.75*

Month total 00-05
Level of casual labour

All industries

0.60*

Monthly data 00-05

More casual labours are associated with more fatalities.

Agriculture, Forestry & Fishing

0.28*

Monthly data 00-05

Agriculture -sub sector:

Horticulture & fruit growing

0.76*

Month total 00-05
Visitors/non-workers attending work sites

All industries

0.59*

Monthly data 00-05

More non-workers attending work sites are associated with more workplace fatalities.

Agriculture -sub sector:

Horticulture & fruit growing

0.74*

Month total 00-05

Manufacturing

0.64*

Month total 00-05
Variation in work activities

Agriculture, Forestry & Fishing

0.28*

Monthly data 00-05

More frequent variation in work activities in agriculture is associated with an increase in fatal incidents.

Construction

-0.41*

Monthly data 00-05

More work varieties in construction are associated with fewer fatalities in this sector.
Work involving vehicles

Agriculture -Sub sector:

Horticulture & fruit growing

0.71*

Month total 00-05

Work involving vehicles is related to an increase in fatal incidents.

Construction

-0.34*

Monthly data 00-05

More vehicle use in work (e.g. prepare the work site and building materials) is related to fewer fatal incidents (possibly as there is less chance of falling from height).

Work under poor weather conditions

All industries

-0.69*

  

The worse the weather, the more likely a fatal incident.
Lack of recovery from fatigue

All industries

0.60*

Monthly data 00-05

Lack of recovery from fatigue is related to an increase in fatal incidents.

Agriculture, Forestry & Fishing

0.33**

Monthly data 00-05

Construction

0.33*

Monthly data 00-05
Tight timescales/ deadlines

Agriculture -Sub sector:

Horticulture & fruit growing

0.75*

Month total 00-05

Tighter timescales or rush work to meet deadlines in this sector are associated with an increase in fatal incidents.
Use of hazardous substances

All industries

0.58*

Monthly data 00-05

An increase in the use of hazardous substances is associated with an increase in workplace fatalities.

 

Environmental factors
Factors Industries the factor is associated with Correlation coefficients & level of significance Note Description
Mean monthly rainfall (mm)

All industries

0.29***

Monthly data 00-05

Higher rainfall is related to more fatal incidents overall.

Cultural, recreational & other services

-0.23**

For these sectors, higher rainfall is associated with fewer fatal incidents. (Possibly due to more indoor/less outdoor activities.)

Manufacturing

-0.22**

Transport & storage

-0.19*
Mean monthly wet days (rainfall≥1mm)

Agriculture, Forestry & Fishing

0.71***

Monthly data 00-05

Wet weather/days are associated with an increase in fatal incidents in the agriculture industry.

Construction

-0.20**

Wet weather/days are related to fewer fatal incidents in these sectors. (Possibly due to more internal work).

Cultural, recreational & other services

-0.23**

Manufacturing

-0.37***
Mean monthly air temperature (°C)

All industries

0.27**

Monthly data 00-05

Higher air temperature is associated with an increase in workplace fatalities (summertime effect)

Agriculture, Forestry & Fishing

0.60***

Cultural, recreational & other services

0.40***

Manufacturing

0.50***
Sunshine (hours)

Agriculture, Forestry & Fishing

0.42***

Monthly data 00-05

More sunshine hours are related to an increase in fatal incidents in these sectors (possibly due to longer work hours).

Cultural, recreational & other services

0.37***

Manufacturing

0.43***

Transport & storage

0.20**
Ground frost (No. of days)

Agriculture, Forestry & Fishing

-0.42***

Monthly data 00-05

More days with ground frost are associated with fewer fatal incidents in these sectors (non-summer season, possibly due to shorter work hours)

Cultural, recreational & other services

-0.35***

Transport & storage

-0.35***
Mean speed of wind (km/h)

Manufacturing

0.18*

Monthly data 00-05

Stronger wind is associated with an increase in fatal incidents.

Transport & storage

0.21**

 

Sociological factors
Factors Industries the factor is associated with Correlation coefficients & level of significance Note Description

Overseas tourist arrivals

Agriculture, Forestry & fishing

0.31*

Monthly data 01-05

An increase in tourists is associated with an increase in fatal incidents in these sectors (also see 'casual labours')

Construction

0.36*

Cultural, recreational & other services

0.58*

Transport & storage

0.57**

Short-term arrivals-NZ residents

Construction

0.49*

Monthly data 00-05

An increase in temporary NZ workers is associated with an increase in fatal incidents.

School holidays

Agriculture, Forestry & Fishing

0.29*

Monthly data 00-05

More fatal incidents tend to happen in school holiday times.

Manufacturing

0.43*

Public holidays

Agriculture, Forestry & Fishing

0.29*

Monthly data 00-05

More fatal incidents are associated with public holidays.

Daylight saving

Agriculture, Forestry & Fishing

0.28*

Monthly data 00-05

More fatalities tend to occur during daylight saving period (overlap with summertime)

Household estimate

Cultural, recreational & other services

-0.53*

  

As household value increases, the number of fatal incidents tends to decrease in this sector.

Consumer Price Index (CPI)

Cultural, recreational & other services

-0.54*

Quarterly data 00-05

As the CPI increases, the number of workplace fatalities tends to decrease in this sector.

Alcohol consumption-beer

All industries

0.41*

Quarterly data 00-05

Alcohol consumption is associated with an increase in workplace fatalities.

Agriculture, Forestry & Fishing

0.65***

Total alcohol consumption

Agriculture, Forestry & Fishing

0.59**

Quarterly data 00-05

Tobacco consumption

Agriculture, Forestry & Fishing

0.42*

Quarterly data 00-05

Smoking is associated with an increase in the occurrence of fatal incidents. (Possibly due to the close correlation between smoking tobacco & drinking alcohol.)

 

Individual factors
Factors Industries the factor is associated with Correlation coefficients & level of significance Note Description

Age

All industries, also for 'Agriculture, forestry & fishing'

Chi2 test

P≤0.05, and confirmed by normalisation

55-64 years old

Higher summertime fatalities

35-44 years old

Higher autumn-time fatalities

Normalisation only

65+

More vulnerable during the autumn

Gender

All industries

Descriptive statistics

88.1% male

8.3% female (see note 17)

The majority of workplace fatalities are male workers.

Employment status

All industries

Descriptive statistics

EMP:56.6%

SE: 23.2%

BS: 15.2%

Most workplace fatalities involved those who were employed, but no significant seasonal trend was found by employment status.

Note: *statistically significant at p≤0.05 level; ** p≤0.01; ***p≤0.001.

 

[14] In these cases the knowledge of the analyst reviewing the report was insufficient to know whether procedures were in place that were violated.

[15] Medium-Long-term Horticulture and Viticulture Seasonal Labour Strategy. Supporting Industries with Seasonal Labour Demands to Achieve Sustainable Growth. Report prepared by The Horticulture and Viticulture Seasonal Working Group, 2005.

[16] Data source: Labour Market Statistics 2005, Part 7: Hours of Work.

[17] Data source: Statistics New Zealand, Oct. 2006.

[18] http://www.fourcorners.co.nz/new-zealand/public-holidays/

[19] http://webexhibits.org/daylightsaving/newZealand.html

[20] There were 13 cases that the victims’ gender was unknown.

[21] There were 18 cases that the victims’ employment status was unknown.