Radiologist Utilization of the EMR

Author

Lu Mao

Published

July 17, 2025

Statistical analysis

Categorical variables are summarized by frequency and percentage. Continuous variables are summarized by median and interquartile range (IQR). The Kruskal-Wallis test is used to compare continuous variables across groups. The Wilcoxon rank-sum test is used to compare continuous variables between two groups. The chi-square test is used to compare categorical variables across groups. The Fisher exact test is used when the expected cell count is less than 5. Temporal trends of EMR usage by category are illustrated using area plot over time. P values < 0.05 are considered statistically significant. All analyeses are performed using R version 4.1.2.

User characteristics and user-level analysis

We first aggregate data at the user level. For each user, the number of months during which they have been using the system is defined as the difference between the latest and earliest dates of their records (ual_date). The total number of hours active is the sum of the active times (number_of_seconds_active), overall and by category (ual_category). Finally, the overall and category-specific hours active per month is the total number of hours divided by the months of usage.

By training status

Table 1: User characteristics and EMR usage by training status.
Characteristic Physician, N = 1471 Physician Assistant, N = 51 Nurse Practitioner, N = 41 p-value2
Years at UW 3 (1, 13) 7 (4, 9) 6 (5, 7) 0.8
    Unknown 1 0 0
Sex


0.004
    Female 42 (29%) 3 (60%) 4 (100%)
    Male 103 (71%) 2 (40%) 0 (0%)
    Unknown 2 0 0
Months of usage 21.2 (10.5, 21.6) 21.5 (21.4, 21.5) 21.6 (16.5, 21.6) 0.7
Monthly hours active - Overall 6 (3, 12) 33 (18, 49) 39 (34, 52) <0.001
Monthly hours active - Clinical Review 2.4 (0.9, 4.7) 20.1 (9.5, 28.4) 22.5 (20.4, 28.4) <0.001
Monthly hours active - Communication 0.12 (0.05, 0.22) 0.62 (0.57, 1.22) 2.62 (1.77, 3.40) <0.001
Monthly hours active - Dashboard 0.15 (0.10, 0.21) 0.16 (0.07, 0.17) 0.08 (0.02, 0.14) 0.3
Monthly hours active - In Basket 0.19 (0.09, 0.39) 2.75 (0.62, 3.59) 1.43 (0.68, 3.47) 0.021
Monthly hours active - Orders 0.04 (0.00, 0.21) 2.27 (0.54, 5.34) 4.82 (3.02, 6.51) <0.001
Monthly hours active - Protocols 0.32 (0.02, 1.00) 0.00 (0.00, 0.00) 0.00 (0.00, 0.02) <0.001
Monthly hours active - Reading Palette 1.24 (0.55, 2.94) 0.00 (0.00, 0.60) 0.00 (0.00, 0.00) <0.001
Monthly hours active - Research 0.003 (0.001, 0.014) 0.008 (0.003, 0.020) 0.004 (0.002, 0.010) 0.8
Monthly hours active - Schedule/Patient Lists 0.55 (0.15, 1.37) 4.94 (2.85, 6.25) 5.34 (4.05, 10.00) <0.001
Monthly hours active - Visit Navigator 0.01 (0.00, 0.05) 1.63 (0.88, 1.70) 1.37 (1.08, 2.28) <0.001
Monthly hours active - Other 0.12 (0.04, 0.23) 0.44 (0.42, 1.22) 0.61 (0.46, 0.69) <0.001
1 Median (IQR); n (%)
2 Kruskal-Wallis rank sum test; Fisher’s exact test

Comments:

  • Physicians spend far less time using EMR than non-physicians, both overall and for each category.
  • NP generally spends more time than PA, largely due to longer time in Clinical Review, Communication, and Orders (despite shorter time in Basket).

The next two sub-sections focus on physicians only.

By physician sex

There is little difference between the sexes.

Table 2: Physician characteristics and EMR usage by sex.
Characteristic Female, N = 421 Male, N = 1031 p-value2
Training status

>0.9
    Physician 42 (100%) 103 (100%)
    Physician Assistant 0 (0%) 0 (0%)
    Nurse Practitioner 0 (0%) 0 (0%)
Years at UW 4 (1, 12) 3 (1, 13) 0.7
    Unknown 1 0
Months of usage 20.2 (11.3, 21.6) 21.4 (9.4, 21.6) >0.9
Monthly hours active - Overall 7 (4, 13) 6 (3, 11) 0.3
Monthly hours active - Clinical Review 2.51 (1.07, 3.87) 2.17 (0.87, 4.83) 0.8
Monthly hours active - Communication 0.15 (0.04, 0.25) 0.12 (0.05, 0.21) 0.5
Monthly hours active - Dashboard 0.15 (0.11, 0.22) 0.14 (0.10, 0.21) 0.5
Monthly hours active - In Basket 0.17 (0.06, 0.63) 0.20 (0.10, 0.36) >0.9
Monthly hours active - Orders 0.01 (0.00, 0.18) 0.04 (0.00, 0.21) 0.6
Monthly hours active - Protocols 0.43 (0.04, 1.13) 0.27 (0.03, 0.95) 0.4
Monthly hours active - Reading Palette 1.9 (0.9, 3.0) 1.2 (0.5, 2.9) 0.086
Monthly hours active - Research 0.002 (0.001, 0.006) 0.005 (0.001, 0.018) 0.007
Monthly hours active - Schedule/Patient Lists 0.51 (0.16, 1.23) 0.58 (0.12, 1.42) >0.9
Monthly hours active - Visit Navigator 0.01 (0.00, 0.06) 0.01 (0.00, 0.04) 0.7
Monthly hours active - Other 0.14 (0.05, 0.23) 0.12 (0.04, 0.25) 0.5
1 n (%); Median (IQR)
2 Fisher’s exact test; Wilcoxon rank sum test

By physician years at UW

Table 3: Physician characteristics and EMR usage by years at UW.
Characteristic 0 - 5, N = 861 5 - 15, N = 371 15+, N = 231 p-value2
Training status


>0.9
    Physician 86 (100%) 37 (100%) 23 (100%)
    Physician Assistant 0 (0%) 0 (0%) 0 (0%)
    Nurse Practitioner 0 (0%) 0 (0%) 0 (0%)
Years at UW 1 (0, 2) 11 (8, 13) 22 (18, 27) <0.001
Sex


0.6
    Female 24 (28%) 12 (33%) 5 (22%)
    Male 61 (72%) 24 (67%) 18 (78%)
    Unknown 1 1 0
Months of usage 13.1 (6.5, 21.5) 21.6 (21.5, 21.6) 21.6 (21.2, 21.6) <0.001
Monthly hours active - Overall 9 (5, 13) 5 (2, 7) 4 (2, 5) <0.001
Monthly hours active - Clinical Review 3.73 (1.63, 5.42) 1.62 (0.54, 2.67) 1.02 (0.68, 1.86) <0.001
Monthly hours active - Communication 0.14 (0.05, 0.26) 0.14 (0.04, 0.22) 0.08 (0.04, 0.14) 0.3
Monthly hours active - Dashboard 0.16 (0.11, 0.22) 0.11 (0.08, 0.17) 0.12 (0.09, 0.18) 0.013
Monthly hours active - In Basket 0.14 (0.07, 0.30) 0.33 (0.12, 0.69) 0.28 (0.17, 0.42) 0.005
Monthly hours active - Orders 0.06 (0.01, 0.25) 0.01 (0.00, 0.09) 0.02 (0.00, 0.05) 0.025
Monthly hours active - Protocols 0.63 (0.16, 1.32) 0.07 (0.01, 0.27) 0.03 (0.00, 0.40) <0.001
Monthly hours active - Reading Palette 2.35 (0.91, 3.18) 0.85 (0.51, 1.45) 0.83 (0.47, 1.23) <0.001
Monthly hours active - Research 0.006 (0.002, 0.021) 0.002 (0.001, 0.009) 0.001 (0.000, 0.005) <0.001
Monthly hours active - Schedule/Patient Lists 0.80 (0.29, 1.52) 0.29 (0.06, 0.85) 0.11 (0.04, 0.54) <0.001
Monthly hours active - Visit Navigator 0.02 (0.00, 0.05) 0.01 (0.00, 0.03) 0.00 (0.00, 0.02) 0.2
Monthly hours active - Other 0.18 (0.09, 0.27) 0.03 (0.02, 0.12) 0.05 (0.03, 0.11) <0.001
1 n (%); Median (IQR)
2 Fisher’s exact test; Kruskal-Wallis rank sum test; Pearson’s Chi-squared test

Comments:

  1. New hires (< 5 years at UW) tend to spend more time, mainly driven by clinical review, schedule/patient lists, Protocols, and Reading Palette.
    • Unclear whether it’s cohort or temporal effect (will be addressed in next section).
Figure 1: Overall and category-specific monthly hours active by physician years at UW.

Temporal analysis

In this section we map out the monthly hours active over time.

By training status

The temporal trend of overall monthly hours active by training status is plotted in Figure 2, and decomposed by category in Figure 3.

Figure 2: Overall median monthly hours active (IQR shaded) over time by training status.
Figure 3: Category-specific median monthly hours active over time by training status.

Comments:

  1. PA and NP spend consistently and substantially more time on EMR than physicians do.
  2. There is no obvious time trend for physicians.

By physician sex

The temporal trend of overall monthly hours active by physician sex is plotted in Figure 4, and decomposed by category in Figure 5.

Figure 4: Overall median monthly hours active (IQR shaded) over time by physician sex.
Figure 5: Category-specific median monthly hours active over time by physician sex.

Comments:

  1. Females tend to spend slightly more time than males, particularly on Reading Palette.

By physician years at UW

The temporal trend of overall monthly hours active by physician years at UW is plotted in Figure 6, and decomposed by category in Figure 7.

Figure 6: Overall median monthly hours active (IQR shaded) over time by physician years at UW.
Figure 7: Category-specific median monthly hours active over time by physician years at UW .

Comments:

  1. Recent hires (\(<\) 5 yrs) tend to spend more time consistently than old hires (cohort effect, not temporal effect);

Physician seniority and division

Data in this section are restricted to 2021-12-01 – 2023-04-30.

Physician seniority

Frequency by training status and period
Characteristic Before 2022-6-30, N = 1101 After 2022-7-1, N = 1171
Training

    Resident 10 (9.8%) 6 (5.4%)
    Fellow 11 (11%) 17 (15%)
    Attending 81 (79%) 89 (79%)
    Unknown 8 5
1 n (%)

The temporal trend of overall monthly hours active by physician seniority is plotted below.

(Exploratory) Overall median monthly hours active (IQR shaded) over time by physician seniority.

Resident has too few data points. Combine it with fellow (Figure 8).

Figure 8: Overall median monthly hours active (IQR shaded) over time by physician seniority.

Summary statistics and formal tests on training status by two periods are tabulated in Table 4. Residents/Fellows spend substantially and significantly more time than attendings.

Table 4: Summary statistics of average monthly hours active by physician seniority and period.
Period Resident/Fellow, N = 341 Attending, N = 891 p-value2
Before 2022-6-30 11.3 (10.0, 13.4) 4.4 (2.5, 6.7) <0.001
After 2022-7-1 12.6 (9.9, 15.0) 4.1 (2.0, 6.7) <0.001
Whole period 12.6 (9.9, 13.7) 4.1 (2.1, 6.6) <0.001
1 Median (IQR)
2 Wilcoxon rank sum test

Physician division - attendings only

Frequency by division and period
Characteristic Before 2022-6-30, N = 811 After 2022-7-1, N = 891
Division

    MSK 9 (11%) 8 (9.0%)
    IR/NeuroIR 13 (16%) 13 (15%)
    Breast 7 (8.6%) 7 (7.9%)
    MRI/Abdominal 17 (21%) 19 (21%)
    Neuro 10 (12%) 12 (13%)
    Peds 5 (6.2%) 8 (9.0%)
    Chest/CV 11 (14%) 11 (12%)
    Community 6 (7.4%) 8 (9.0%)
    Nucs 3 (3.7%) 3 (3.4%)
1 n (%)

Because there is no switch in division, we focus on the whole period. Breast spends more time than other divisions (Figure 9 and Table 5).

Figure 9: Boxplots of whole-period average monthly hours active by physician division.
Table 5: Summary statistics of average monthly hours active by physician division.
Period Breast, N = 71 Chest/CV, N = 111 Community, N = 81 IR/NeuroIR, N = 131 MRI/Abdominal, N = 181 MSK, N = 91 Neuro, N = 121 Nucs, N = 31 Peds, N = 81 p-value2
Whole period 13.2 (11.9, 14.0) 4.0 (2.6, 7.0) 2.0 (1.8, 3.5) 6.7 (5.3, 8.4) 3.9 (1.8, 4.7) 4.8 (4.1, 5.3) 2.0 (1.1, 3.2) 4.1 (2.6, 5.1) 3.0 (1.8, 4.1) <0.001
1 Median (IQR)
2 Kruskal-Wallis rank sum test
Breast vs other
Period Breast, N = 71 Other, N = 821 p-value2
Whole period 13.2 (11.9, 14.0) 4.0 (2.0, 6.2) <0.001
1 Median (IQR)
2 Wilcoxon rank sum test
Breast vs other (no trainee, attendings only)
Period Breast, N = 71 Other, N = 821 p-value2
Whole period 13.2 (11.9, 14.0) 4.0 (2.0, 6.2) <0.001
1 Median (IQR)
2 Wilcoxon rank sum test

The temporal trend of overall monthly hours active for by Breast vs other is plotted in Figure 10, and decomposed by category in Figure 11.

Figure 10: Overall median monthly hours active (IQR shaded) over time by physician division.
Figure 11: Category-specific median monthly hours active over time by physician division.
Figure 12: Category-specific (without reading palette) median monthly hours active over time by physician division (attendings only).
Table 6: User characteristics and EMR usage by division.
Characteristic Breast, N = 71 Other, N = 831 p-value2
Years at UW 10 (5, 12) 10 (4, 16) 0.6
Sex

0.021
    Female 5 (71%) 21 (26%)
    Male 2 (29%) 61 (74%)
    Unknown 0 1
Monthly hours active - Overall 13.2 (11.9, 14.0) 4.0 (2.0, 6.3) <0.001
Monthly hours active - Overall (w/o Reading Palette) 5.0 (4.7, 5.6) 2.9 (1.3, 4.9) 0.027
Monthly hours active - Clinical Review 2.68 (2.03, 2.84) 1.23 (0.55, 2.43) 0.039
Monthly hours active - Communication 0.17 (0.15, 0.21) 0.15 (0.06, 0.26) 0.4
Monthly hours active - Dashboard 0.33 (0.31, 0.36) 0.12 (0.08, 0.16) <0.001
Monthly hours active - In Basket 0.72 (0.34, 0.88) 0.22 (0.09, 0.51) 0.026
Monthly hours active - Orders 0.01 (0.00, 0.02) 0.04 (0.01, 0.10) 0.11
Monthly hours active - Protocols 0.21 (0.12, 0.25) 0.07 (0.02, 0.34) 0.3
Monthly hours active - Reading Palette 7.98 (6.97, 8.69) 0.85 (0.48, 1.21) <0.001
Monthly hours active - Research 0.008 (0.005, 0.040) 0.006 (0.003, 0.012) 0.3
Monthly hours active - Schedule/Patient Lists 1.20 (0.80, 1.38) 0.20 (0.06, 0.64) 0.003
Monthly hours active - Visit Navigator 0.00 (0.00, 0.01) 0.01 (0.00, 0.03) 0.10
Monthly hours active - Other 0.11 (0.07, 0.19) 0.06 (0.03, 0.18) 0.2
1 Median (IQR); n (%)
2 Wilcoxon rank sum test; Fisher’s exact test

Comment:

  1. The difference between breast vs other is driven by Reading Palette.
  2. Without Reading Palette, breast still spends more time than other divisions (\(p=0.026\)).

Table 7 below summarizes the user characteristics and EMR usage by division, restricted to attendings only (same as Table 6).

Table 7: User (attendings only) characteristics and EMR usage by division.
Characteristic Breast, N = 71 Other, N = 831 p-value2
Years at UW 10 (5, 12) 10 (4, 16) 0.6
Sex

0.021
    Female 5 (71%) 21 (26%)
    Male 2 (29%) 61 (74%)
    Unknown 0 1
Monthly hours active - Overall 13.2 (11.9, 14.0) 4.0 (2.0, 6.3) <0.001
Monthly hours active - Overall (w/o Reading Palette) 5.0 (4.7, 5.6) 2.9 (1.3, 4.9) 0.027
Monthly hours active - Clinical Review 2.68 (2.03, 2.84) 1.23 (0.55, 2.43) 0.039
Monthly hours active - Communication 0.17 (0.15, 0.21) 0.15 (0.06, 0.26) 0.4
Monthly hours active - Dashboard 0.33 (0.31, 0.36) 0.12 (0.08, 0.16) <0.001
Monthly hours active - In Basket 0.72 (0.34, 0.88) 0.22 (0.09, 0.51) 0.026
Monthly hours active - Orders 0.01 (0.00, 0.02) 0.04 (0.01, 0.10) 0.11
Monthly hours active - Protocols 0.21 (0.12, 0.25) 0.07 (0.02, 0.34) 0.3
Monthly hours active - Reading Palette 7.98 (6.97, 8.69) 0.85 (0.48, 1.21) <0.001
Monthly hours active - Research 0.008 (0.005, 0.040) 0.006 (0.003, 0.012) 0.3
Monthly hours active - Schedule/Patient Lists 1.20 (0.80, 1.38) 0.20 (0.06, 0.64) 0.003
Monthly hours active - Visit Navigator 0.00 (0.00, 0.01) 0.01 (0.00, 0.03) 0.10
Monthly hours active - Other 0.11 (0.07, 0.19) 0.06 (0.03, 0.18) 0.2
1 Median (IQR); n (%)
2 Wilcoxon rank sum test; Fisher’s exact test

Breast

Table 8: User characteristics in Breast division and EMR usage by training status.
Characteristic Fellow, N = 01 Attending, N = 71 p-value2
Years at UW NA (NA, NA) 10.0 (4.5, 12.0)
Sex

>0.9
    Female 0 (NA%) 5 (71%)
    Male 0 (NA%) 2 (29%)
Monthly hours active - Overall NA (NA, NA) 13 (12, 14)
Monthly hours active - Overall (w/o Reading Palette) NA (NA, NA) 5.0 (4.7, 5.6)
Monthly hours active - Clinical Review NA (NA, NA) 2.68 (2.03, 2.84)
Monthly hours active - Communication NA (NA, NA) 0.17 (0.15, 0.21)
Monthly hours active - Dashboard NA (NA, NA) 0.33 (0.31, 0.36)
Monthly hours active - In Basket NA (NA, NA) 0.72 (0.34, 0.88)
Monthly hours active - Orders NA (NA, NA) 0.005 (0.004, 0.019)
Monthly hours active - Protocols NA (NA, NA) 0.21 (0.12, 0.25)
Monthly hours active - Reading Palette NA (NA, NA) 8.0 (7.0, 8.7)
Monthly hours active - Research NA (NA, NA) 0.008 (0.005, 0.040)
Monthly hours active - Schedule/Patient Lists NA (NA, NA) 1.20 (0.80, 1.38)
Monthly hours active - Other NA (NA, NA) 0.11 (0.07, 0.19)
Monthly hours active - Visit Navigator NA (NA, NA) 0.004 (0.000, 0.009)
1 Median (IQR); n (%)
2 Fisher’s exact test

The temporal trend of overall monthly hours active for Breast physicians by training status is plotted in Figure 13, and decomposed by category in Figure 14.

Figure 13: Overall monthly hours active (thick line, median) over time for Breast physicians by training status.

Comments:

  1. Generally attending << fellow. But there is an outlying attending (GEGIOS, ALISON R), which makes the test only borderline significant given the small sample size (Table 8).
Figure 14: Category-specific median monthly hours active over time for Breast physicians by training status.

Attending vs. Trainee (residents/fellows)

User characteristics and EMR usage by training status are summarized in Table 9. The temporal trend of overall monthly hours active for training status is plotted in Figure 15.

Table 9: User characteristics and EMR usage by training status.
Characteristic Resident/Fellow, N = 341 Attending, N = 901 p-value2
Years at UW 1 (1, 2) 10 (4, 16) <0.001
    Unknown 1 0
Sex

>0.9
    Female 10 (30%) 26 (29%)
    Male 23 (70%) 63 (71%)
    Unknown 1 1
Monthly hours active - Overall 12.6 (9.9, 13.7) 4.2 (2.1, 6.7) <0.001
Monthly hours active - Overall (w/o Reading Palette) 8.4 (7.4, 10.6) 3.0 (1.4, 5.1) <0.001
Monthly hours active - Clinical Review 5.29 (4.12, 5.88) 1.27 (0.63, 2.60) <0.001
Monthly hours active - Communication 0.19 (0.06, 0.28) 0.16 (0.06, 0.26) 0.6
Monthly hours active - Dashboard 0.17 (0.12, 0.20) 0.13 (0.08, 0.19) 0.030
Monthly hours active - In Basket 0.12 (0.09, 0.19) 0.24 (0.09, 0.57) 0.009
Monthly hours active - Orders 0.26 (0.09, 0.39) 0.04 (0.00, 0.09) <0.001
Monthly hours active - Protocols 1.08 (0.68, 1.53) 0.10 (0.02, 0.34) <0.001
Monthly hours active - Reading Palette 2.97 (2.49, 3.36) 0.91 (0.50, 1.48) <0.001
Monthly hours active - Research 0.010 (0.004, 0.033) 0.006 (0.003, 0.013) 0.065
Monthly hours active - Schedule/Patient Lists 1.11 (0.70, 1.61) 0.23 (0.06, 0.71) <0.001
Monthly hours active - Visit Navigator 0.05 (0.01, 0.08) 0.01 (0.00, 0.03) 0.003
Monthly hours active - Other 0.20 (0.12, 0.42) 0.06 (0.03, 0.18) <0.001
1 Median (IQR); n (%)
2 Wilcoxon rank sum test; Pearson’s Chi-squared test
Figure 15: Category-specific median monthly hours active over time by training status.