Wrong calculation of accrual intensity for fixed sample survival design

[fpahlke]

Example where $accrualIntensity is wrong

What I get

I’m trying to find the absolute accrual intensity (number recruited per time unit) when
recruitment is twice as fast in the second period as the first.

sampleSize <- getSampleSizeSurvival(alpha = 0.025, 
    sided = 1, 
    beta = 0.1,
    hazardRatio = 0.7, 
    lambda2 = log(2) / 9,
    accrualTime = c(0, 3, 12),
    accrualIntensity = c(0.1, 0.2),
    accrualIntensityType = "relative",
    followUpTime = 6)
sampleSize$accrualIntensity

[1] 215.90555 53.97639

What I expect

...so doing this manually for now

m <- sampleSize$maxNumberOfSubjects

Accrual per month during first 3 months

m / (3 * 0.1 + 9 * 0.2) * 0.1

[1] 30.84365

Accrual per month during months 4 to 9

m / (3 * 0.1 + 9 * 0.2) * 0.2

[1] 61.6873

[fpahlke]

We fixed the issue. The accrual intensity now will be calculated correctly and we added a new test case to out unit tests.