Enriching knowledge and enhancing care through health data

Impact of unreliable health data on decision making

Good quality of health data is imperative for valid and reliable decision making. However, several studies have demonstrated that Real World Data today is of variable quality, and is often not fit for the intended reuse purpose.

The “Electronic Health Records for Clinical Research” (EHR4CR) project, funded by the Innovative Medicine Initiative (IMI), clearly demonstrated that many variables, among which even simple ones such as patient weight, are frequently not present within EHR systems (Doods, Botteri, Dugas, & Fritz, 2014 (1)).

Figure 1 shows an excerpt from the EHR4CR standardised data inventory, where availability of the respective items across hospital sites is color coded, ranging from green (all data available) to red (no data available). Black cells indicate that the variable was not included in the EHR system.  


Figure 1: EHR4CR standardised data inventory. Color code indicates completeness of data (green = 100% complete; red = 0% complete; black = variable not included in EHR system). Figure modified from Doods, Botteri, Dugas, & Fritz (2014) (1) 


Further, a pilot data quality assessment at Hospital del Mar in Barcelona (Spain) revealed errors in patients’ height and weight measurements, as shown in Figure 2. The green circle highlights extreme but valid data points, originating from infants, whereas the red circle highlights data points that are extreme and very unlikely to be true. Weight and height measurements of these patients were most likely reversed. 

















Figure 2: Height and weight measures of patients with heart failure at the Hospital del Mar, Barcelona, Spain. Green circle highlights extreme but valid data points (i.e., children), whereas the red circle highlights data points that are extreme and very unlikely to be true. 

Incorrect or absent recording of patient weights, though, can lead to medication dosage errors.


34% of weight errors led to medication-dosing errors (2)

48% of patients required additional monitoring, examination or treatment after
medication errors resulting from weight errors (3)


Hirata and colleagues (2019) examined the frequency and consequences of weight errors that occurred at one children’s hospital and two general hospitals. To this end, they investigated 79,000 emergency department encounters of children under the age of 5. They revealed that, although weight errors across all three hospitals were relatively low (0.63% on average), a large proportion of weight errors led to subsequent medication-dosing errors (34% on average).


Table 1. Consequences of weight errors. Table modified from Hirata et al. (2019) (2)


Children’s Hospital
(n = 237)

hospital 1
(n = 62)

hospital 2
(n = 70)


Led to medication error

80 (34%) 26 (42%) 18 (26%)
  No medication-dosing error beacause of weight correction 40 (17%) 6 (10%) 5 (7%)
  No medication-dosing error and weight uncorrected 117 (49%) 30 (48%) 47 (67%)


An earlier study by Selbst and colleagues (1999) also investigated the consequences of medication errors in a pediatric emergency department. Even if this is an older study, the results are equally significant, as shown in Table 2: almost half of the patients required additional monitoring (30%), examination (6%) or treatment (12%) after medication errors resulting from weight errors.


Table 2. Severity levels for medication errors. Table modified from Selbst et al. (1999) (3)


Level of severity

Number of patients


Level 1: No injury to patient

17 (52%)
  Level 2: Increased monitoring needed, no change in vital signs, no patient harm 10 (30%)
  Level 3: Further laboratory studies needed, no ultimate harm
2 (6%)
  Level 4: Another drug needed for treatment, or increased length of stay
4 (12%)
  Level 5: Permanent patient harm
  Level 6: Patient death






(1) Doods, J., Botteri, F., Dugas, M., & Fritz, F. (2014). A European inventory of common electronic health record data elements for clinical trial feasibility. Trials, 15(1), 1–10. https://doi.org/10.1186/1745-6215-15-1

(2) Hirata, K. M., Kang, A. H., Ramirez, G. V., Kimata, C., & Yamamoto, L. G. (2019). Pediatric Weight Errors and Resultant Medication Dosing Errors in the Emergency Department. Pediatric Emergency Care, 35(9), 637–642. https://doi.org/10.1097/PEC.0000000000001277

(3) Selbst, S. M., Fein, J. A., Osterhoudt, K., & Ho, W. (1999). Medication errors in a pediatric emergency department. Pediatric Emergency Care, 15(1), 1–4. https://doi.org/10.1097/00006565-199902000-00001