"There is compelling high-level research evidence that when shifts are below target, all patients are exposed to risk and some patients will suffer consequent harms."
Because the consequences of inadequate staffing were often not immediately apparent it was difficult to ascribe a particular shift to a particular patient-harm event, Lawless, a registered nurse, said.
"However, it is not necessary to have this level of information to know that shifts below staffing target are not tolerable."
The report, commissioned by SDHB chief nursing and midwifery officer Jane Wilson, set out to examine how the board was managing the care capacity demand management (CCDM) programme, an agreed safe-staffing regime.
All health boards have been obliged to hire several new nurses to meet CCDM requirements but Southern, like many other boards, seems unlikely to be able to do so.
Nurses are in short supply nationwide for many reasons, including border restrictions imposed due to Covid-19 making overseas recruitment problematic.
DHBs have been recruiting aged-care nurses, which has created a consequent staff shortage in aged-care facilities.
Lawless said the SDHB had a strong and ongoing commitment to CCDM, but at the end of last year had reached only 71 per cent of its target number of nurses.
Her report examined staffing levels in three wards, and noted that while short-staffing was a regular, persistent and concerning problem, there were also some equally unsatisfactory days when too many nurses had been rostered on.
"These represent a poor investment of health resources and lost productivity because staff time, once committed, cannot be reinvested at a future date."
Ward 4C at Dunedin Hospital, an inpatient ward with 26 beds, showed a chronic pattern of under-target shifts, Lawless said.
Evening shifts were also regularly understaffed, but night shifts were usually on or above target.
"A pattern of late discharges means that more patients are present for more of the shift, adding to nursing workload."
Southland Hospital's assessment, treatment and rehabilitation ward generally maintained an acceptable staffing level, but Southland's 38-bed medical ward had a high turnover of patients, high bed occupancy, late discharges and low length of stay, which had significant implications for nursing workload, Lawless said.
"A large number of day shifts are under target staffing. There is some evidence of a seasonal pattern with the winter months likely to be more poorly staffed," Lawless said.
"There are relatively few day shifts that exceed the target staffing hours."
Lawless said her principal recommendation was that the SDHB prioritise elimination of understaffed shifts as a central goal because of the association with patient risk and harm.
The SDHB has been on a recruitment drive for nurses in recent months and earlier this year hired several new graduates. However, this has meant its nursing staffing budget has overrun.
Wilson said the review and other recent reports had helped determine priorities for the nursing budget for 2021-22.
"The report recommends other opportunities to improve operational efficiency by better matching workforce to demand.
"A number of recommendations related to improving workforce management ... are already being progressed."
