TABLE 1.
DCE attributes and levels
| Attribute | Description | Levels |
|---|---|---|
| Type | Colonoscopy: This test is conducted in a clinic or hospital. A trained physician will insert a thin, flexible tube with a camera into the rectum and inspect the colon. Sedation is required. You will be required to limit your food intake to specific foods (low‐fiber) a few days before and to fluids only the day before. Preparation also includes drinking a laxative (about half a gallon) the evening before the test, and the morning of the test. The laxative will cause diarrhea to clear the bowels and can in some cases cause dizziness, nausea, or vomiting. |
(1) Colonoscopy (2) At‐home stool‐based test (3) Blood test |
| At‐home stool‐based test: A test kit will be given to the patients. The kit includes all materials required for taking a stool sample and posting it to a dedicated laboratory. The stool will be collected in a sample container and sealed in a bag, before returning it for testing. Some tests may require adding provided chemicals to the stool sample in the sample container. In the case of a positive finding, meaning potential cancer was identified, a follow‐up colonoscopy should be undertaken to confirm the finding. | ||
| Blood test: A blood sample is taken by a healthcare professional in a local clinic or hospital. The healthcare professional collects a routine sample of blood by inserting a needle into a vein in the arm. The blood will then be analyzed in a laboratory. In the case of a positive finding, meaning a potential cancer was identified, a follow‐up colonoscopy should be undertaken to confirm the finding. | ||
| Frequency a | This is how often (in years) the screening test is supposed to be conducted according to medical guidelines. Screening more often than what is recommended by the guidelines may not necessarily increase the chance of finding a potential cancer. |
(1) Every year (2) Every 3 years (3) Every 10 years |
| True‐positive b |
The true‐positive rate is the proportion of tested individuals with cancer, who are correctly identified by the test as having cancer. Thus, the higher the true‐positive rate, the higher is the chance of finding cancer, if it exists. For example, a true‐positive rate of 9 out of 10 (90%) means that out of 10 tested individuals with cancer, 9 (90%) are correctly identified as having cancer. The remaining individual (10%) with cancer is incorrectly identified as not having cancer, despite actually having cancer (false negative). |
(1) 6 out of 10 (60%) (2) 7 out of 10 (70%) (3) 8 out of 10 (80%) (4) 9 out of 10 (90%) (5) 10 out of 10 (100%) |
| True‐negative |
The true‐negative rate is the proportion of tested individuals with no cancer, who are correctly identified by the test as not having cancer. A high true‐negative rate increases the risk of unnecessary procedures (e.g., additional follow‐up colonoscopies). For example, a true‐negative rate of 9 out of 10 (90%) means that out of 10 tested individuals with no cancer, 9 (90%) are correctly told they do not have cancer. The remaining individual (10%) without cancer is incorrectly identified as having cancer despite being cancer‐free (false positive). |
(1) 7 out of 10 (70%) (2) 8 out of 10 (80%) (3) 9 out of 10 (90%) (4) 10 out of 10 (100%) |
| Adenoma true‐positive rate c (physicians only) |
Adenoma true‐positive rate refers to correctly identifying those with polyps that are at risk of developing cancer in the future. For example, an adenoma true‐positive rate of 2 out of 10 (20%) means that out of 10 polyps that are at risk of developing into cancer in the future, 2 (20%) were correctly identified by the test (true positives), and 8 (80%) were incorrectly identified (false negatives). |
(1) 2 out of 10 (20%) (2) 5 out of 10 (50%) (3) 10 out of 10 (100%) |
‘Every year’ not available for colonoscopy choice option.
‘70%’ not available for colonoscopy choice option.
‘20%’ not available for colonoscopy choice option.