Direct observation to record hand hygiene behaviour in hospitals and clinics is considered the gold standard in compliance monitoring, but it has some inherent disadvantages. One of them is the Hawthorne Effect. But how high is its influence really, and what alternatives are available to hygiene professionals?
In the midst of the current coronavirus pandemic, it is once again clear how important careful hand hygiene is for infection control. But aside from a major outbreak, thorough hand hygiene is an integral part of basic hygiene and plays a key role in patient care in medical facilities.
Each year, more than 600,000 people in Germany suffer from a nosocomial infection. Up to 20,000 of these cases prove fatal.  Not all of these cases can be prevented, but a certain percentage can. Experts estimate that up to 30 percent of all hospital-acquired infections can be avoided, with a large proportion of prevented through strict adherence to hand hygiene rules.  The World Health Organization (WHO) explicitly defines five moments for hand hygiene for which hospital staff must carry out hand disinfection as part of patient care. Under the WHO’s 5 Moments model, in an internal intensive care unit, a total of 218 moments for hygienic hand disinfection can be incurred per patient day. 
Appearances can be deceptive in hand hygiene compliance
What potential does thorough hand hygiene offer to prevent nosocomial infections? In reviewing 2018 data from the National Reference Center for Surveillance of Nosocomial Infections (NRZ), from more than 420 hospitals, hand disinfection is common – three out of four necessary hand disinfections are performed. In intensive care units, a compliance rate of almost 80 percent is achieved. 
“Due to the Hawthorne effect, direct observation is unsuitable for determining real hand hygiene compliance! However, it is indispensable for determining the indications, describing the hand hygiene quality (technique, rub-in time) and personal feedback. Electronic monitoring systems can help to determine the actual compliance much more objectively.”Dr. Andreas Glöckner, MD
These compliance rates are calculated based on direct observation. In practice, this means that a trained person observes whether doctors and nurses are carrying out hygienic hand disinfection at the required time. However, this method can lead to changes in behaviour, simply because the subject is aware that they are being observed. Therefore, any collected data are biased and often do not reflect actual compliance rates. This change in behaviour, as a result of direct observation, is known as the “Hawthorne Effect”.
The Hawthorne Effect has been well studied in the field of hospital hygiene and especially hand hygiene. Harvard professors Elton Mayo and Fritz Roethlisberger carried out a number of studies on this phenomenon in the 1920s and 1930s.
Hawthorne Effect in relation to hand hygiene
More recently, one Canadian study, conducted in 2014 by Jocelyn Srigley and colleagues, demonstrated hospital staff performed three times more hand disinfections when being observed, compared to times when no observer was present, in the exact same location. 
A team led by Stefan Hagel from the University Hospital of Jena also quantified the Hawthorne Effect in a scientific study. During the direct observation phase of the study, observers noted an average of 21 hand disinfections per hour. In a second phase of the study, researchers used the OPHARDT Hygiene Monitoring System and electronic hand disinfectant dispensers to record each individual hand hygiene event. No direct observer was present for this part of the study. In contrast to earlier results, only 8 hand disinfections were carried out per hour.  A 2.6-fold increase in hand hygiene events were recorded in the first phase, due to the Hawthorne Effect.
A recent study from March 2020 reached similar results. Direct observation of hand hygiene led to an increase of 2.5 times in hand disinfections performed on two transplant wards of a hospital, compared to results without an observer present, measured by electronic hand hygiene dispensers. 
How do we obtain valid hand hygiene data?
The findings are clear. To gain a real understanding of hand hygiene compliance in medical facilities, direct observation is not enough.
Measuring hand hygiene using electronic monitoring systems is increasingly becoming the tool of choice to remove observer bias. As an added benefit to these systems, hygiene managers have 24/7 access to hand hygiene data, measured continuously and fully automatically via intelligent disinfectant dispensers. With just a click of a button, corresponding evaluation programs can provide detailed reports on hand hygiene events, including dispenser location, time of activation, and amount of disinfectant dispensed. The Robert Koch Institute (RKI) recommends a quantity of at least 3 ml of disinfectant per hand hygiene event.
The renowned Commission for Hospital Hygiene and Infection Prevention (KRINKO), affiliated with the RKI, also notes the advantages of monitoring hand hygiene compliance electronically, and the feedback that can be provided to hospital staff using such a system.  This feedback plays an increasingly important role in improving compliance in the long term. The intelligent hygiene dispensers now even go as far as providing feedback on hand hygiene behavior directly to medical staff from the dispenser itself, as seen in the ingo-man® SmartNose. Staff can directly see that the required volume disinfectant has been dispensed, based on the LED located at the top of the dispenser.
A possible accusation that electronic systems do not record whether hand disinfections have been carried out in relation to a WHO-defined moment for hand hygiene, is contradicted by further results from the above mentioned study by Hagel. In the study, only 5 percent of all hand hygiene events observed did not correspond to the known “5 moments”.
Therefore, the compliance values measured should be considered in context. Even so, there is great potential in hand hygiene to prevent nosocomial infections, while at the same time, mitigate increasing antibiotic resistance. With electronic monitoring systems we ensure that we have a reliable measuring tool that helps us improve hand hygiene behaviour over the long-term.
 Zacher, Benedikt, et al. “Application of a new methodology and R package reveals a high burden of healthcare-associated infections (HAI) in Germany compared to the average in the European Union/European Economic Area, 2011 to 2012.” Eurosurveillance 24.46 (2019).
 Gastmeier, P., et al. “Wie viele nosokomiale Infektionen sind vermeidbar?.” DMW-Deutsche Medizinische Wochenschrift 135.03 (2010): 91-93.
 Stahmeyer, J. T., et al. “Hand hygiene in intensive care units: a matter of time?.” Journal of Hospital Infection 95.4 (2017): 338-343.
 Nationales Referenzzentrum für Surveillance von nosokomialen Infektionen. Modul HAND-KISS_S Referenzdaten 2018.
 Srigley, Jocelyn A., et al. “Quantification of the Hawthorne effect in hand hygiene compliance monitoring using an electronic monitoring system: a retrospective cohort study.” BMJ Qual Saf 23.12 (2014): 974-980.
 Hagel, Stefan, et al. “Quantifying the Hawthorne effect in hand hygiene compliance through comparing direct observation with automated hand hygiene monitoring.” infection control & hospital epidemiology 36.8 (2015): 957-962.
 Vaisman, Alon, et al. “Out of sight, out of mind: a prospective observational study to estimate the duration of the Hawthorne effect on hand hygiene events.” BMJ Quality & Safety (2020).
 Kommission für Krankenhaushygiene und Infektionsprävention beim Robert Koch-Institut “Händehygiene in Einrichtungen des Gesundheitswesens.” Bundesgesundheitsblatt-Gesundheitsforschung-Gesundheitsschutz 9 (2016): 1189.