Dear stata users,

I am writing to you about the calculation of numbers at risk post sts graph. I am studying the time (suivi) until the event "conversion".

My data are as follows. When I run the command sts graph, risktable.

The numbers at risks are :

time 0 : 375 patients

time 2 : 327 patients

time 4 : 287 patients

time 6 : 110 patients.

I do not understand because during the follow-up, 105 patients have the event "conversion". I thought the numbers at risk represented at each time, the number of patients who don't have done the event so far. Normally at 6 years follow up (the max), 105 patients did the event so 270 did not and are still at risk isnt'it?

Could you explain me how this number at risk is calculated and what it means exactly. I don't understand how 110 patients can be "at risk" at 6 years follow-up? It doesn't make sense.

Thank you in advance for your help,

LR

I am writing to you about the calculation of numbers at risk post sts graph. I am studying the time (suivi) until the event "conversion".

My data are as follows. When I run the command sts graph, risktable.

The numbers at risks are :

time 0 : 375 patients

time 2 : 327 patients

time 4 : 287 patients

time 6 : 110 patients.

I do not understand because during the follow-up, 105 patients have the event "conversion". I thought the numbers at risk represented at each time, the number of patients who don't have done the event so far. Normally at 6 years follow up (the max), 105 patients did the event so 270 did not and are still at risk isnt'it?

Could you explain me how this number at risk is calculated and what it means exactly. I don't understand how 110 patients can be "at risk" at 6 years follow-up? It doesn't make sense.

Thank you in advance for your help,

LR

Code:

* Example generated by -dataex-. To install: ssc install dataex clear input int id float suivi byte conversion 1 2 1 2 5 0 3 5 0 4 6 0 5 6 0 6 5 0 7 6 0 8 1 1 9 1 1 10 5 0 11 6 0 12 1 1 13 4 1 14 5 0 16 5 0 17 6 1 18 5 0 20 2 1 21 6 0 22 5 0 23 3 0 24 5 0 26 5 0 27 5 0 28 4 1 29 6 0 30 1 1 31 2 1 32 5 0 33 6 0 34 5 0 35 2 0 36 1 1 38 5 0 39 5 0 40 5 0 41 5 0 42 5 0 43 5 0 44 5 0 45 5 0 46 5 0 47 6 0 48 3 1 49 6 0 51 1 1 52 1 1 53 5 0 54 6 0 55 6 0 56 2 1 57 5 0 58 6 0 59 5 0 60 5 0 61 5 0 62 1 1 63 5 1 64 2 1 65 1.5 1 66 4 1 67 5 0 69 6 0 70 1 1 71 5 0 72 3 0 73 2 0 74 1 1 75 5 0 76 1 1 77 6 0 78 5 0 79 3 1 80 5 0 81 6 0 82 2 1 83 6 0 84 6 0 85 3 1 86 5 0 87 1 1 88 6 0 89 1.5 1 90 5 0 91 6 0 92 5 0 93 6 0 94 1 1 95 5 0 96 5 0 97 5 0 98 1 1 99 3 0 100 6 0 101 5 0 102 5 0 103 4 1 104 5 0 105 3 1 106 6 0 end

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