From 2cc027a028f1c826bd29a641dae0ee9630dc4708 Mon Sep 17 00:00:00 2001
From: sbidari <zib2@cdc.gov>
Date: Wed, 16 Oct 2024 17:32:42 -0400
Subject: [PATCH] add details about sample target

---
 hub-config/tasks.json  |  8 +++++---
 model-output/README.md | 16 +++++++++++++---
 2 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/hub-config/tasks.json b/hub-config/tasks.json
index e648f21..e83a08e 100644
--- a/hub-config/tasks.json
+++ b/hub-config/tasks.json
@@ -132,12 +132,14 @@
                         "sample": {
                             "output_type_id_params": {
                                 "is_required": false,
-                                "type": "integer",
+                                "type": "character",
+                                "max_length": 15,
                                 "min_samples_per_task": 100,
-                                "max_samples_per_task": 100
+                                "max_samples_per_task": 100,
+                                "compound_taskid_set": ["reference_date"]
                             },
                             "value": {
-                                "type": "integer",
+                                "type": "double",
                                 "minimum": 0
                             }
                         }
diff --git a/model-output/README.md b/model-output/README.md
index 7fc86f7..0062c7a 100644
--- a/model-output/README.md
+++ b/model-output/README.md
@@ -169,7 +169,7 @@ Values in the `output_type` column are either
 -   "quantile" or
 -   "samples".
 
-This value indicates whether that row corresponds to a quantile forecast or sample trajectories for weekly incident hospital admissions.
+This value indicates whether that row corresponds to a quantile forecast or sample trajectories for weekly incident hospital admissions. Samples can be submitted either for individual modeling tasks, where each `horizon` and `location` is treated independently, or as a part of a compound modeling task that encodes dependencies across forecast `horizon` and `location`.
 
 ### `output_type_id`
 Values in the `output_type_id` column specify identifying information for the output type.
@@ -217,8 +217,18 @@ Teams must provide the following 23 quantiles:
 
 #### sample output
 
-When the predictions are samples, values in the `output_type_id` column are indexes for the samples. 
-*More details to be added here*
+When the predictions are samples, values in the `output_type_id` column are indexes for the samples. The `output_type_id` is used to indicate the dependence across multiple task id variables when samples come from a joint predictive distribution. For example, samples from a joint predictive distribution across `horizon`, will share `output_type_id` for predictions for different horizons within a same `location` as below:
+
+| origin_date|horizon| location | output_type| output_type_id | value |
+|:---------- |:-----:|:-----:| :-------- | :------------ | :---- |
+| 2024-10-15 | -1    |  MA | sample | s0 | - |
+| 2024-10-15 |  0      |  MA | sample | s0 | - |
+| 2024-10-15 | 1       |  MA | sample | s0 | - |
+| 2024-10-15 | -1      |  MA | sample | s1 | - |
+| 2024-10-15 |  0      |  MA | sample | s1 | - |
+| 2024-10-15 |  1      |  MA | sample | s1 | - |
+
+Here, `output_type_id = s0` specifies that the predictions for horizons -1, 0, and 1 are part of the same joint distribution. More details on sample output can be found in the [hubverse documentation of sample output type](https://hubverse.io/en/latest/user-guide/sample-output-type.html).
 
 ### `value`