diff --git a/README.md b/README.md
index 4b8203dfaf..7b62189a59 100644
--- a/README.md
+++ b/README.md
@@ -27,6 +27,7 @@ Recommended practices
 - Should be [incremental]
 - Should filter input tables on partition and clustering columns
 - Should use `_` prefix in generated column names not meant for output
+- Should use `_bits` suffix for any integer column that represents a bit pattern
 - Should not use `DATETIME` type, due to incompatiblity with
   [spark-bigquery-connector]
 - Should use the earliest row for each `document_id` by `submission_timestamp`
diff --git a/sql/clients_last_seen_raw_v1.init.sql b/sql/clients_last_seen_raw_v1.init.sql
new file mode 100644
index 0000000000..3a86490a40
--- /dev/null
+++ b/sql/clients_last_seen_raw_v1.init.sql
@@ -0,0 +1,24 @@
+CREATE TABLE
+  clients_last_seen_raw_v1
+PARTITION BY
+  submission_date
+CLUSTER BY
+  sample_id,
+  client_id AS
+SELECT
+  CAST(NULL AS DATE) AS submission_date,
+  0 AS days_seen_bits,
+  0 AS days_visited_5_uri_bits,
+  0 AS days_opened_dev_tools_bits,
+  0 AS days_since_created_profile,
+  CAST(NULL AS BOOLEAN) ping_seen_within_6_days_of_profile_creation,
+  -- We make sure to delay * until the end so that as new columns are added
+  -- to clients_daily, we can add those columns in the same order to the end
+  -- of this schema, which may be necessary for the daily join query between
+  -- the two tables to validate.
+  * EXCEPT (submission_date_s3)
+FROM
+  clients_daily_v6
+WHERE
+  -- Output empty table and read no input rows
+  FALSE
diff --git a/sql/clients_last_seen_raw_v1.sql b/sql/clients_last_seen_raw_v1.sql
new file mode 100644
index 0000000000..7efa8e1d6b
--- /dev/null
+++ b/sql/clients_last_seen_raw_v1.sql
@@ -0,0 +1,74 @@
+-- Equivalent to, but more efficient than, calling udf_bitmask_range(1, 28)
+CREATE TEMP FUNCTION bitmask_lowest_28() AS (0x0FFFFFFF);
+--
+CREATE TEMP FUNCTION shift_one_day(x INT64) AS (IFNULL((x << 1) & bitmask_lowest_28(), 0));
+--
+CREATE TEMP FUNCTION combine_days(prev INT64, curr INT64) AS (shift_one_day(prev) + IFNULL(curr, 0));
+--
+WITH
+  _current AS (
+  SELECT
+    -- In this raw table, we capture the history of activity over the past
+    -- 28 days for each usage criterion as a single 64-bit integer. The
+    -- rightmost bit represents whether the user was active in the current day.
+    CAST(TRUE AS INT64) AS days_seen_bits,
+    -- For measuring Active MAU, where this is the days since this
+    -- client_id was an Active User as defined by
+    -- https://docs.telemetry.mozilla.org/cookbooks/active_dau.html
+    CAST(scalar_parent_browser_engagement_total_uri_count_sum >= 5 AS INT64) AS days_visited_5_uri_bits,
+    CAST(devtools_toolbox_opened_count_sum > 0 AS INT64) AS days_opened_dev_tools_bits,
+    DATE_DIFF(submission_date_s3, SAFE.PARSE_DATE("%F", SUBSTR(profile_creation_date, 0, 10)), DAY) AS days_since_created_profile,
+    CAST(NULL AS BOOLEAN) AS ping_seen_within_6_days_of_profile_creation,
+    * EXCEPT (submission_date_s3)
+  FROM
+    clients_daily_v6
+  WHERE
+    submission_date_s3 = @submission_date ),
+  --
+  _previous AS (
+  SELECT
+    * EXCEPT (submission_date)
+    REPLACE (
+    -- Scrub values outside 28 day window.
+    IF(days_since_created_profile BETWEEN 0 AND 26, days_since_created_profile, NULL) AS days_since_created_profile)
+  FROM
+    clients_last_seen_raw_v1 AS cls
+  WHERE
+    submission_date = DATE_SUB(@submission_date, INTERVAL 1 DAY)
+    -- Filter out rows from yesterday that have now fallen outside the 28-day window.
+    AND shift_one_day(days_seen_bits) > 0),
+  --
+  _joined AS (
+  SELECT
+    @submission_date AS submission_date,
+    IF(_current.client_id IS NOT NULL,
+      _current,
+      _previous).* REPLACE (
+        combine_days(_previous.days_seen_bits, _current.days_seen_bits) AS days_seen_bits,
+        combine_days(_previous.days_visited_5_uri_bits, _current.days_visited_5_uri_bits) AS days_visited_5_uri_bits,
+        combine_days(_previous.days_opened_dev_tools_bits, _current.days_opened_dev_tools_bits) AS days_opened_dev_tools_bits,
+        -- We want to base new profile creation date on the first profile_creation_date
+        -- value we observe, so we propagate an existing non-null value in preference
+        -- to a non-null value on today's observation.
+        COALESCE(_previous.days_since_created_profile + 1,
+          _current.days_since_created_profile) AS days_since_created_profile,
+        -- We only trust profile_creation_date if we see a ping within one week,
+        -- so we calculate this on day 6 and propagate to subsequent days.
+        IF(COALESCE(_previous.days_since_created_profile + 1,
+        _current.days_since_created_profile) = 6, TRUE, _previous.ping_seen_within_6_days_of_profile_creation) AS ping_seen_within_6_days_of_profile_creation)
+  FROM
+    _current
+  FULL JOIN
+    _previous
+  USING
+    -- Include sample_id to match the clustering of the tables, which may improve
+    -- join performance.
+    (sample_id, client_id))
+  --
+SELECT
+  * REPLACE (
+    -- Null out any fields that may contain data leaked from beyond our 28 day window.
+    IF(days_since_created_profile BETWEEN 0 AND 27, days_since_created_profile, NULL) AS days_since_created_profile,
+    IF(days_since_created_profile BETWEEN 0 AND 27, ping_seen_within_6_days_of_profile_creation, NULL) AS ping_seen_within_6_days_of_profile_creation)
+FROM
+  _joined
diff --git a/sql/clients_last_seen_v1.init.sql b/sql/clients_last_seen_v1.init.sql
deleted file mode 100644
index 9b966a19c2..0000000000
--- a/sql/clients_last_seen_v1.init.sql
+++ /dev/null
@@ -1,10 +0,0 @@
-SELECT
-  DATE(NULL) AS submission_date,
-  * EXCEPT (submission_date_s3),
-  0 AS days_since_seen,
-  NULL AS days_since_visited_5_uri
-FROM
-  clients_daily_v6
-WHERE
-  -- Output empty table and read no input rows
-  FALSE
diff --git a/sql/clients_last_seen_v1.sql b/sql/clients_last_seen_v1.sql
index 24cfec6fcb..9904ef6793 100644
--- a/sql/clients_last_seen_v1.sql
+++ b/sql/clients_last_seen_v1.sql
@@ -1,44 +1,10 @@
-WITH
-  _current AS (
-  SELECT
-    * EXCEPT (submission_date_s3, fxa_configured),
-    0 AS days_since_seen,
-    -- For measuring Active MAU, where this is the days since this
-    -- client_id was an Active User as defined by
-    -- https://docs.telemetry.mozilla.org/cookbooks/active_dau.html
-    IF(scalar_parent_browser_engagement_total_uri_count_sum >= 5,
-      0,
-      NULL) AS days_since_visited_5_uri,
-    fxa_configured
-  FROM
-    clients_daily_v6
-  WHERE
-    submission_date_s3 = @submission_date ),
-  _previous AS (
-  SELECT
-    * EXCEPT (submission_date) REPLACE(
-      -- omit values outside 28 day window
-      IF(days_since_visited_5_uri < 27,
-        days_since_visited_5_uri,
-        NULL) AS days_since_visited_5_uri)
-  FROM
-    clients_last_seen_v1
-  WHERE
-    submission_date = DATE_SUB(@submission_date, INTERVAL 1 DAY)
-    AND clients_last_seen_v1.days_since_seen < 27 )
+CREATE OR REPLACE VIEW
+  `moz-fx-data-derived-datasets.telemetry.clients_last_seen_v1` AS
 SELECT
-  @submission_date AS submission_date,
-  IF(_current.client_id IS NOT NULL,
-    _current,
-    _previous).* EXCEPT (days_since_seen,
-      days_since_visited_5_uri),
-  COALESCE(_current.days_since_seen,
-    _previous.days_since_seen + 1) AS days_since_seen,
-  COALESCE(_current.days_since_visited_5_uri,
-    _previous.days_since_visited_5_uri + 1) AS days_since_visited_5_uri
+  -- We cannot use UDFs in a view, so we paste the body of udf_bitpos(bits) literally here.
+  CAST(SAFE.LOG(days_seen_bits & -days_seen_bits, 2) AS INT64) AS days_since_seen,
+  CAST(SAFE.LOG(days_visited_5_uri_bits & -days_visited_5_uri_bits, 2) AS INT64) AS days_since_visited_5_uri,
+  CAST(SAFE.LOG(days_opened_dev_tools_bits & -days_opened_dev_tools_bits, 2) AS INT64) AS days_since_opened_dev_tools,
+  *
 FROM
-  _current
-FULL JOIN
-  _previous
-USING
-  (client_id)
+  `moz-fx-data-derived-datasets.telemetry.clients_last_seen_raw_v1`
diff --git a/tests/clients_last_seen_v1/test_backfill/clients_last_seen_v1.csv b/tests/clients_last_seen_raw_v1/test_backfill/clients_last_seen_raw_v1.csv
similarity index 100%
rename from tests/clients_last_seen_v1/test_backfill/clients_last_seen_v1.csv
rename to tests/clients_last_seen_raw_v1/test_backfill/clients_last_seen_raw_v1.csv
diff --git a/tests/clients_last_seen_v1/test_backfill/daily.csv b/tests/clients_last_seen_raw_v1/test_backfill/daily.csv
similarity index 100%
rename from tests/clients_last_seen_v1/test_backfill/daily.csv
rename to tests/clients_last_seen_raw_v1/test_backfill/daily.csv
diff --git a/tests/clients_last_seen_v1/test_backfill/expect.csv b/tests/clients_last_seen_raw_v1/test_backfill/expect.csv
similarity index 100%
rename from tests/clients_last_seen_v1/test_backfill/expect.csv
rename to tests/clients_last_seen_raw_v1/test_backfill/expect.csv
diff --git a/tests/clients_last_seen_v1/test_empty_input.yaml b/tests/clients_last_seen_raw_v1/test_empty_input.yaml
similarity index 100%
rename from tests/clients_last_seen_v1/test_empty_input.yaml
rename to tests/clients_last_seen_raw_v1/test_empty_input.yaml
diff --git a/tests/clients_last_seen_raw_v1/test_single_day/clients_daily_v6.ndjson b/tests/clients_last_seen_raw_v1/test_single_day/clients_daily_v6.ndjson
new file mode 100644
index 0000000000..ca2e7f64a7
--- /dev/null
+++ b/tests/clients_last_seen_raw_v1/test_single_day/clients_daily_v6.ndjson
@@ -0,0 +1,2 @@
+{"submission_date_s3":"2019-01-02","active_hours_sum":1.0,"devtools_toolbox_opened_count_sum":2.0,"profile_creation_date":"2018-12-27 00:00:00","attribution":{"source":"test"},"client_id":"b","sample_id":0}
+{"submission_date_s3":"2019-01-02","active_hours_sum":1.0,"devtools_toolbox_opened_count_sum":0.0,"profile_creation_date":"2018-09-01 00:00:00","attribution":{"source":"test"},"client_id":"c","sample_id":0}
diff --git a/tests/clients_last_seen_v1/test_single_day/clients_daily_v6.schema.json b/tests/clients_last_seen_raw_v1/test_single_day/clients_daily_v6.schema.json
similarity index 72%
rename from tests/clients_last_seen_v1/test_single_day/clients_daily_v6.schema.json
rename to tests/clients_last_seen_raw_v1/test_single_day/clients_daily_v6.schema.json
index e1aee2ec0b..9e00de403b 100644
--- a/tests/clients_last_seen_v1/test_single_day/clients_daily_v6.schema.json
+++ b/tests/clients_last_seen_raw_v1/test_single_day/clients_daily_v6.schema.json
@@ -10,11 +10,26 @@
     "type": "STRING",
     "mode": "REQUIRED"
   },
+  {
+    "name": "sample_id",
+    "type": "INTEGER",
+    "mode": "REQUIRED"
+  },
   {
     "name": "active_hours_sum",
     "type": "FLOAT",
     "mode": "REQUIRED"
   },
+  {
+    "name": "devtools_toolbox_opened_count_sum",
+    "type": "FLOAT",
+    "mode": "REQUIRED"
+  },
+  {
+    "name": "profile_creation_date",
+    "type": "STRING",
+    "mode": "NULLABLE"
+  },
   {
     "name": "attribution",
     "type": "RECORD",
diff --git a/tests/clients_last_seen_raw_v1/test_single_day/clients_last_seen_raw_v1.ndjson b/tests/clients_last_seen_raw_v1/test_single_day/clients_last_seen_raw_v1.ndjson
new file mode 100644
index 0000000000..464efbf599
--- /dev/null
+++ b/tests/clients_last_seen_raw_v1/test_single_day/clients_last_seen_raw_v1.ndjson
@@ -0,0 +1,3 @@
+{"submission_date":"2019-01-01","active_hours_sum":0.0,"devtools_toolbox_opened_count_sum":2.0,"attribution":{"source":"prev"},"client_id":"a","sample_id":0,"days_seen_bits":3,"days_opened_dev_tools_bits":1}
+{"submission_date":"2019-01-01","active_hours_sum":0.0,"devtools_toolbox_opened_count_sum":0.0,"attribution":{"source":"prev"},"client_id":"b","sample_id":0,"days_seen_bits":0}
+{"submission_date":"2019-01-01","active_hours_sum":0.0,"devtools_toolbox_opened_count_sum":2.0,"attribution":{"source":"prev"},"client_id":"d","sample_id":0,"days_seen_bits":0}
diff --git a/tests/clients_last_seen_v1/test_single_day/clients_last_seen_v1.schema.json b/tests/clients_last_seen_raw_v1/test_single_day/clients_last_seen_raw_v1.schema.json
similarity index 54%
rename from tests/clients_last_seen_v1/test_single_day/clients_last_seen_v1.schema.json
rename to tests/clients_last_seen_raw_v1/test_single_day/clients_last_seen_raw_v1.schema.json
index cb093ffbfe..d16d25c4eb 100644
--- a/tests/clients_last_seen_v1/test_single_day/clients_last_seen_v1.schema.json
+++ b/tests/clients_last_seen_raw_v1/test_single_day/clients_last_seen_raw_v1.schema.json
@@ -1,4 +1,29 @@
 [
+  {
+    "name": "days_seen_bits",
+    "type": "INT64",
+    "mode": "REQUIRED"
+  },
+  {
+    "name": "days_visited_5_uri_bits",
+    "type": "INT64",
+    "mode": "NULLABLE"
+  },
+  {
+    "name": "days_opened_dev_tools_bits",
+    "type": "INT64",
+    "mode": "NULLABLE"
+  },
+  {
+    "name": "days_since_created_profile",
+    "type": "INT64",
+    "mode": "NULLABLE"
+  },
+  {
+    "name": "ping_seen_within_6_days_of_profile_creation",
+    "type": "BOOLEAN",
+    "mode": "NULLABLE"
+  },
   {
     "name": "submission_date",
     "type": "DATE",
@@ -9,11 +34,26 @@
     "type": "STRING",
     "mode": "REQUIRED"
   },
+  {
+    "name": "sample_id",
+    "type": "INTEGER",
+    "mode": "REQUIRED"
+  },
   {
     "name": "active_hours_sum",
     "type": "FLOAT",
     "mode": "REQUIRED"
   },
+  {
+    "name": "devtools_toolbox_opened_count_sum",
+    "type": "FLOAT",
+    "mode": "REQUIRED"
+  },
+  {
+    "name": "profile_creation_date",
+    "type": "STRING",
+    "mode": "NULLABLE"
+  },
   {
     "name": "attribution",
     "type": "RECORD",
@@ -31,16 +71,6 @@
     "type": "INT64",
     "mode": "NULLABLE"
   },
-  {
-    "name": "days_since_seen",
-    "type": "INT64",
-    "mode": "REQUIRED"
-  },
-  {
-    "name": "days_since_visited_5_uri",
-    "type": "INT64",
-    "mode": "NULLABLE"
-  },
   {
     "name": "fxa_configured",
     "type": "BOOLEAN",
diff --git a/tests/clients_last_seen_raw_v1/test_single_day/expect.ndjson b/tests/clients_last_seen_raw_v1/test_single_day/expect.ndjson
new file mode 100644
index 0000000000..32f6d0c597
--- /dev/null
+++ b/tests/clients_last_seen_raw_v1/test_single_day/expect.ndjson
@@ -0,0 +1,3 @@
+{"submission_date": "2019-01-02", "days_seen_bits": 6, "days_visited_5_uri_bits": 0, "days_opened_dev_tools_bits": 2, "client_id": "a", "sample_id": 0, "active_hours_sum": 0.0, "devtools_toolbox_opened_count_sum": 2.0, "attribution": {"source": "prev"}}
+{"submission_date": "2019-01-02", "days_seen_bits": 1, "days_visited_5_uri_bits": 0, "days_opened_dev_tools_bits": 1, "days_since_created_profile": 6, "ping_seen_within_6_days_of_profile_creation": true, "client_id": "b", "sample_id": 0, "active_hours_sum": 1.0, "devtools_toolbox_opened_count_sum": 2.0, "profile_creation_date": "2018-12-27 00:00:00", "attribution": {"source": "test"}}
+{"submission_date": "2019-01-02", "days_seen_bits": 1, "days_visited_5_uri_bits": 0, "days_opened_dev_tools_bits": 0, "client_id": "c", "sample_id": 0, "active_hours_sum": 1.0, "devtools_toolbox_opened_count_sum": 0.0, "profile_creation_date": "2018-09-01 00:00:00", "attribution": {"source": "test"}}
diff --git a/tests/clients_last_seen_v1/test_single_day/query_params.yaml b/tests/clients_last_seen_raw_v1/test_single_day/query_params.yaml
similarity index 100%
rename from tests/clients_last_seen_v1/test_single_day/query_params.yaml
rename to tests/clients_last_seen_raw_v1/test_single_day/query_params.yaml
diff --git a/tests/clients_last_seen_v1/test_single_day/clients_daily_v6.ndjson b/tests/clients_last_seen_v1/test_single_day/clients_daily_v6.ndjson
deleted file mode 100644
index 02bfeaa181..0000000000
--- a/tests/clients_last_seen_v1/test_single_day/clients_daily_v6.ndjson
+++ /dev/null
@@ -1,2 +0,0 @@
-{"submission_date_s3":"2019-01-02","active_hours_sum":1.0,"attribution":{"source":"test"},"client_id":"b"}
-{"submission_date_s3":"2019-01-02","active_hours_sum":1.0,"attribution":{"source":"test"},"client_id":"c"}
diff --git a/tests/clients_last_seen_v1/test_single_day/clients_last_seen_v1.ndjson b/tests/clients_last_seen_v1/test_single_day/clients_last_seen_v1.ndjson
deleted file mode 100644
index d834d53943..0000000000
--- a/tests/clients_last_seen_v1/test_single_day/clients_last_seen_v1.ndjson
+++ /dev/null
@@ -1,2 +0,0 @@
-{"submission_date":"2019-01-01","active_hours_sum":0.0,"attribution":{"source":"prev"},"client_id":"a","days_since_seen":0}
-{"submission_date":"2019-01-01","active_hours_sum":0.0,"attribution":{"source":"prev"},"client_id":"b","days_since_seen":0}
diff --git a/tests/clients_last_seen_v1/test_single_day/expect.ndjson b/tests/clients_last_seen_v1/test_single_day/expect.ndjson
deleted file mode 100644
index 0079fc4f4f..0000000000
--- a/tests/clients_last_seen_v1/test_single_day/expect.ndjson
+++ /dev/null
@@ -1,3 +0,0 @@
-{"submission_date":"2019-01-02","client_id":"a","active_hours_sum":0.0,"attribution":{"source":"prev"},"days_since_seen":1}
-{"submission_date":"2019-01-02","client_id":"b","active_hours_sum":1.0,"attribution":{"source":"test"},"days_since_seen":0}
-{"submission_date":"2019-01-02","client_id":"c","active_hours_sum":1.0,"attribution":{"source":"test"},"days_since_seen":0}
diff --git a/tests/test_generated.py b/tests/test_generated.py
index a7a69ff714..4132fb28e6 100644
--- a/tests/test_generated.py
+++ b/tests/test_generated.py
@@ -3,7 +3,7 @@
 # file, you can obtain one at http://mozilla.org/MPL/2.0/.
 """Automatically generated tests."""
 
-from google.api_core.exceptions import NotFound
+from google.api_core.exceptions import BadRequest, NotFound
 from google.cloud import bigquery
 from .util import coerce_result, generate_tests
 
@@ -58,7 +58,11 @@ def tables(bq, dataset, generated_test):
                     break  # stop because there can only be one time partitioning field
         with open(table.source_path, "rb") as file_obj:
             job = bq.load_table_from_file(file_obj, destination, job_config=job_config)
-        job.result()
+        try:
+            job.result()
+        except BadRequest:
+            print(job.errors)
+            raise
     # clean up handled by default_dataset fixture
 
 
@@ -76,5 +80,6 @@ def test_generated(bq, dataset, generated_test):
     job = bq.query(generated_test.modified_query, job_config=job_config)
     result = list(coerce_result(*job.result()))
     result.sort(key=lambda row: json.dumps(row))
+    generated_test.expect.sort(key=lambda row: json.dumps(row))
 
     assert generated_test.expect == result
diff --git a/udf/udf_bitmask_range.sql b/udf/udf_bitmask_range.sql
new file mode 100644
index 0000000000..09e74ed2d8
--- /dev/null
+++ b/udf/udf_bitmask_range.sql
@@ -0,0 +1,31 @@
+CREATE TEMP FUNCTION
+  udf_bitmask_range( start_ordinal INT64,
+    _length INT64) AS ((
+    SELECT
+      SUM(1 << (_n - 1))
+    FROM
+      UNNEST(GENERATE_ARRAY(start_ordinal, start_ordinal + _length - 1)) AS _n ));
+
+/*
+
+Returns a bitmask that can be used to return a subset of an integer representing
+a bit array. The start_ordinal argument is an integer specifying the starting
+position of the slice, with start_ordinal = 1 indicating the first bit.
+The length argument is the number of bits to include in the mask.
+
+The arguments were chosen to match the semantics of the SUBSTR function; see
+https://cloud.google.com/bigquery/docs/reference/standard-sql/functions-and-operators#substr
+
+Examples:
+
+SELECT udf_bitmask_range(1, 1);
+1
+
+SELECT udf_bitmask_range(2, 4);
+30
+
+-- Taking just the second and third bits (from the right) of binary 11011 should give us 00010 (decimal 2)
+SELECT ((1 << 4) + (1 << 3) + (1 << 1) + (1 << 0)) & udf_range_bitmask(2, 2);
+2
+
+*/
diff --git a/udf/udf_bitpos.sql b/udf/udf_bitpos.sql
new file mode 100644
index 0000000000..9939e73898
--- /dev/null
+++ b/udf/udf_bitpos.sql
@@ -0,0 +1,30 @@
+CREATE TEMP FUNCTION
+  udf_bitpos( bits INT64 ) AS ( CAST(SAFE.LOG(bits & -bits, 2) AS INT64));
+
+/*
+
+Returns a 0-based index of the rightmost set bit in the passed bit pattern
+or null if no bits are set (bits = 0).
+
+To determine this position, we take a bitwise AND of the bit pattern and
+its complement, then we determine the position of the bit via base-2 logarithm;
+see https://stackoverflow.com/a/42747608/1260237
+
+Examples:
+
+SELECT udf_bitpos(0);
+null
+
+SELECT udf_bitpos(1);
+0
+
+SELECT udf_bitpos(2);
+1
+
+SELECT udf_bitpos(8);
+3
+
+SELECT udf_bitpos(8 + 1);
+0
+
+*/