diff --git a/cumulus_library/studies/core/manifest.toml b/cumulus_library/studies/core/manifest.toml
index 1d5a4628..d6db0562 100644
--- a/cumulus_library/studies/core/manifest.toml
+++ b/cumulus_library/studies/core/manifest.toml
@@ -23,7 +23,8 @@ file_names = [
     "observation_vital_signs.sql",
     "medication_request.sql",
     "study_period.sql",
-    "count_core.sql"
+    "count_core.sql",
+    "soe_sequence_of_events.sql"
 ]
 
 [export_config]
@@ -38,4 +39,7 @@ export_list = [
     "core__count_medicationrequest_month",
     "core__meta_date",
     "core__meta_version",
+    "core__count_soe_cond_week",
+    "core__count_soe_document_week",
+    "core__count_soe_medreq_week"
 ]
diff --git a/cumulus_library/studies/core/soe_sequence_of_events.sql b/cumulus_library/studies/core/soe_sequence_of_events.sql
new file mode 100644
index 00000000..405b9d44
--- /dev/null
+++ b/cumulus_library/studies/core/soe_sequence_of_events.sql
@@ -0,0 +1,465 @@
+-- SOE "Sequence of Events" links FHIR resources based on encounter reference
+-- and FHIR resource datetime "period". Ideally, every FHIR resource references
+-- an encounter. The primary function of the SOE tables and counts is QA/Verification.
+--
+-- ###########################################################################
+-- Encounter
+-- Encounter specifies the start/end period from which other FHIR resources can
+-- be mapped. This is useful when FHIR Resource.encounter.reference is missing.
+--
+-- # length of stay calculations
+-- from Karen Olson
+--  LOS= discharge date/time - admit date/time
+--  EDLOS= checkout date/time - check-in date/time
+--  check-in date/time generally = admit date/time, sometimes it's off a little
+--  Care_class= Emergency is ED only
+--  An encounter with care_class= Inpatient or Observation can include time in the ED
+--  If patient was admitted from the ED, THEN only encounter.
+--
+CREATE TABLE core__soe AS
+WITH soe_rawdata AS (
+    SELECT DISTINCT
+        date(from_iso8601_timestamp(e.period."start")) AS enc_start_date,
+        date(from_iso8601_timestamp(e.period."end")) AS enc_end_date,
+        cast(
+            from_iso8601_timestamp(e.period."start") AS timestamp
+        ) AS enc_start_datetime,
+        cast(from_iso8601_timestamp(e.period."end") AS timestamp) AS enc_end_datetime,
+        e.class AS enc_class,
+        subject.reference AS subject_ref,
+        concat('Encounter/', e.id) AS encounter_ref
+    FROM encounter AS e
+)
+
+SELECT DISTINCT
+    enc_start_date,
+    enc_end_date,
+    enc_start_datetime,
+    enc_end_datetime,
+    enc_class,
+    subject_ref,
+    encounter_ref,
+    date_diff('hour', enc_start_datetime, enc_end_datetime) AS los_hours,
+    date_diff('day', enc_start_date, enc_end_date) AS los_days
+FROM soe_rawdata
+WHERE enc_start_date BETWEEN date('2016-01-01') AND current_date;
+
+-- ###########################################################################
+-- Condition
+
+CREATE TABLE core__soe_cond AS
+WITH soe_cond_rawdata AS (
+    SELECT DISTINCT
+        cast(
+            from_iso8601_timestamp(c.recordeddate) AS timestamp
+        ) AS cond_recorded_datetime,
+        cast(
+            from_iso8601_timestamp(c.onsetdatetime) AS timestamp
+        ) AS cond_onset_datetime,
+        c.subject.reference AS subject_ref,
+        c.encounter.reference AS encounter_ref,
+        c.category,
+        concat('Condition/', c.id) AS condition_ref
+    FROM condition AS c
+),
+
+cond AS (
+    SELECT DISTINCT
+        scr.cond_recorded_datetime,
+        scr.cond_onset_datetime,
+        scr.subject_ref,
+        scr.encounter_ref,
+        scr.category,
+        scr.condition_ref,
+        t2.category_row
+    FROM soe_cond_rawdata AS scr,
+        unnest(category) AS t (category_coding),
+        unnest(category_coding.coding) AS t2 (category_row)
+    WHERE scr.cond_recorded_datetime BETWEEN date('2016-01-01') AND current_date
+),
+
+cond_link_reference AS (
+    SELECT DISTINCT
+        cond.cond_recorded_datetime,
+        cond.cond_onset_datetime,
+        cond.condition_ref,
+        cs.enc_start_date,
+        cs.enc_end_date,
+        cs.enc_start_datetime,
+        cs.enc_end_datetime,
+        cs.enc_class,
+        cs.subject_ref,
+        cs.encounter_ref,
+        cs.los_hours,
+        cs.los_days
+    FROM cond, core__soe AS cs
+    WHERE
+        cond.encounter_ref IS NOT NULL
+        AND cond.encounter_ref = cs.encounter_ref
+),
+
+cond_link_period AS (
+    SELECT DISTINCT
+        cond.cond_recorded_datetime,
+        cond.cond_onset_datetime,
+        cond.condition_ref,
+        cs.enc_start_date,
+        cs.enc_end_date,
+        cs.enc_start_datetime,
+        cs.enc_end_datetime,
+        cs.enc_class,
+        cs.subject_ref,
+        cs.encounter_ref,
+        cs.los_hours,
+        cs.los_days
+    FROM cond, core__soe AS cs
+    WHERE
+        cond.encounter_ref IS NULL
+        AND cond.subject_ref = cs.subject_ref
+        AND (
+            (
+                cond.cond_recorded_datetime
+                BETWEEN cs.enc_start_datetime
+                AND cs.enc_end_datetime
+            )
+            OR
+            (
+                cond.cond_onset_datetime
+                BETWEEN cs.enc_start_datetime
+                AND cs.enc_end_datetime
+            )
+        )
+)
+
+SELECT DISTINCT
+    cond.category_row AS category,
+    date(cond.cond_recorded_datetime) AS cond_recorded_date,
+    date(cond.cond_onset_datetime) AS cond_onset_date,
+    cond.cond_recorded_datetime,
+    cond.cond_onset_datetime,
+    lr.encounter_ref AS encounter_ref,
+    lp.encounter_ref AS period_ref,
+    coalesce(lr.encounter_ref, lp.encounter_ref) AS encounter_link,
+    coalesce(lr.enc_class, lp.enc_class) AS enc_class,
+    -- condition and subject must match.
+    cond.subject_ref,
+    cond.condition_ref
+FROM cond
+LEFT JOIN cond_link_period AS lp ON cond.condition_ref = lp.condition_ref
+LEFT JOIN cond_link_reference AS lr ON cond.condition_ref = lr.condition_ref;
+
+-- ###########################################################################
+-- MedicationRequest
+
+CREATE TABLE core__soe_medreq AS
+WITH soe_medreq_rawdata AS (
+    SELECT DISTINCT
+        cast(
+            from_iso8601_timestamp(mr.authoredon) AS timestamp
+        ) AS medreq_authored_datetime,
+        mr.subject.reference AS subject_ref,
+        mr.encounter.reference AS encounter_ref,
+        mr.id AS medreq_id,
+        mr.status AS status,
+        concat('MedicationRequest/', mr.id) AS medreq_ref,
+        mr.medicationreference.reference AS medication_ref
+    FROM medicationrequest AS mr
+),
+
+medreq AS (
+    SELECT DISTINCT
+        medreq_authored_datetime,
+        subject_ref,
+        encounter_ref,
+        medreq_id,
+        status,
+        medreq_ref,
+        medication_ref
+    FROM soe_medreq_rawdata
+    WHERE medreq_authored_datetime BETWEEN date('2016-01-01') AND current_date
+),
+
+soe_medreq_link_reference AS (
+    SELECT DISTINCT
+        medreq.medreq_authored_datetime,
+        medreq.medreq_ref,
+        cs.enc_start_date,
+        cs.enc_end_date,
+        cs.enc_start_datetime,
+        cs.enc_end_datetime,
+        cs.enc_class,
+        cs.subject_ref,
+        cs.encounter_ref,
+        cs.los_hours,
+        cs.los_days
+    FROM medreq, core__soe AS cs
+    WHERE
+        medreq.encounter_ref IS NOT NULL
+        AND medreq.encounter_ref = cs.encounter_ref
+),
+
+soe_medreq_link_period AS (
+    SELECT DISTINCT
+        medreq.medreq_authored_datetime,
+        medreq.medreq_ref,
+        cs.enc_start_date,
+        cs.enc_end_date,
+        cs.enc_start_datetime,
+        cs.enc_end_datetime,
+        cs.enc_class,
+        cs.subject_ref,
+        cs.encounter_ref,
+        cs.los_hours,
+        cs.los_days
+    FROM medreq, core__soe AS cs
+    WHERE
+        medreq.encounter_ref IS NULL
+        AND medreq.subject_ref = cs.subject_ref
+        AND medreq.medreq_authored_datetime
+        BETWEEN cs.enc_start_datetime AND cs.enc_end_datetime
+)
+
+SELECT DISTINCT
+    medreq.status,
+    date(medreq.medreq_authored_datetime) AS medreq_recorded_date,
+    medreq.medreq_authored_datetime,
+    lr.encounter_ref AS encounter_ref,
+    lp.encounter_ref AS period_ref,
+    coalesce(lr.encounter_ref, lp.encounter_ref) AS encounter_link,
+    coalesce(lr.enc_class, lp.enc_class) AS enc_class,
+    -- condition AND subject must match.
+    medreq.subject_ref,
+    medreq.medreq_ref
+FROM medreq
+LEFT JOIN soe_medreq_link_period AS lp ON medreq.medreq_ref = lp.medreq_ref
+LEFT JOIN soe_medreq_link_reference AS lr ON medreq.medreq_ref = lr.medreq_ref;
+
+-- ###########################################################################
+-- DocumentReference
+
+CREATE TABLE core__soe_document AS
+WITH soe_document_rawdata AS (
+    SELECT DISTINCT
+        cast(
+            from_iso8601_timestamp(context.period."start") AS timestamp
+        ) AS doc_start_datetime,
+        cast(
+            from_iso8601_timestamp(context.period."end") AS timestamp
+        ) AS doc_end_datetime,
+        doc.subject.reference AS subject_ref,
+        doc.context,
+        doc.id AS doc_id,
+        concat('DocumentReference/', doc.id) AS doc_ref
+    FROM documentreference AS doc
+),
+
+document AS (
+    SELECT DISTINCT
+        doc_start_datetime,
+        doc_end_datetime,
+        subject_ref,
+        context,
+        doc_id,
+        doc_ref
+    FROM soe_document_rawdata
+    WHERE
+        (doc_start_datetime BETWEEN date('2016-01-01') AND current_date)
+        OR (doc_end_datetime BETWEEN date('2016-01-01') AND current_date)
+),
+
+document_enc AS (
+    SELECT DISTINCT
+        d.doc_start_datetime,
+        d.doc_end_datetime,
+        d.subject_ref,
+        d.context,
+        d.doc_id,
+        d.doc_ref,
+        t.context_encounter.reference AS encounter_ref
+    FROM
+        document AS d,
+        unnest(context.encounter) AS t (context_encounter)
+),
+
+doc_link_period AS (
+    SELECT DISTINCT
+        document.doc_start_datetime,
+        document.doc_end_datetime,
+        document.doc_ref,
+        cs.enc_start_date,
+        cs.enc_end_date,
+        cs.enc_start_datetime,
+        cs.enc_end_datetime,
+        cs.enc_class,
+        cs.subject_ref,
+        cs.encounter_ref,
+        cs.los_hours,
+        cs.los_days
+    FROM document, core__soe AS cs
+    WHERE
+        document.subject_ref = cs.subject_ref
+        AND (
+            (
+                document.doc_start_datetime
+                BETWEEN cs.enc_start_datetime
+                AND cs.enc_end_datetime
+            )
+            OR
+            (
+                document.doc_end_datetime
+                BETWEEN cs.enc_start_datetime
+                AND cs.enc_end_datetime
+            )
+        )
+),
+
+doc_link_reference AS (
+    SELECT DISTINCT
+        document_enc.doc_start_datetime,
+        document_enc.doc_end_datetime,
+        document_enc.doc_ref,
+        cs.enc_start_date,
+        cs.enc_end_date,
+        cs.enc_start_datetime,
+        cs.enc_end_datetime,
+        cs.enc_class,
+        cs.subject_ref,
+        cs.encounter_ref,
+        cs.los_hours,
+        cs.los_days
+    FROM document_enc, core__soe AS cs
+    WHERE
+        document_enc.encounter_ref IS NOT NULL
+        AND document_enc.encounter_ref = cs.encounter_ref
+)
+
+SELECT DISTINCT
+    document.doc_ref,
+    document.doc_start_datetime,
+    document.doc_end_datetime,
+    lr.encounter_ref AS encounter_ref,
+    lp.encounter_ref AS period_ref,
+    -- link REF via Encounter.reference when provided, ELSE link Encounter.period
+    coalesce(lr.encounter_ref, lp.encounter_ref) AS encounter_link,
+    -- link CLASS via Encounter.reference when provided, ELSE link Encounter.period
+    coalesce(lr.enc_class, lp.enc_class) AS enc_class,
+    -- document must match
+    document.subject_ref
+FROM document
+LEFT JOIN doc_link_period AS lp ON document.doc_ref = lp.doc_ref
+LEFT JOIN doc_link_reference AS lr ON document.doc_ref = lr.doc_ref;
+
+-- ###########################################################################
+-- Sequence Of Events, COUNTS
+--
+-- COUNT Condition by week
+CREATE TABLE core__count_soe_cond_week AS
+WITH discrete AS (
+    SELECT
+        core__soe_cond.condition_ref,
+        enc_class.display AS enc_class_display,
+        enc_class.system AS enc_class_system,
+        date_trunc('week', core__soe_cond.cond_recorded_date) AS cond_recorded_week,
+        coalesce(
+            core__soe_cond.cond_onset_date IS NOT NULL, FALSE
+        ) AS cond_onset_date_exists,
+        coalesce(
+            core__soe_cond.encounter_ref IS NOT NULL, FALSE
+        ) AS encounter_ref_exists,
+        coalesce(
+            core__soe_cond.period_ref IS NOT NULL, FALSE
+        ) AS period_ref_exists
+    FROM core__soe_cond
+)
+
+SELECT
+    count(DISTINCT condition_ref) AS cnt,
+    enc_class_system,
+    enc_class_display,
+    cond_recorded_week,
+    cond_onset_date_exists,
+    encounter_ref_exists,
+    period_ref_exists
+FROM discrete
+GROUP BY cube(
+    enc_class_system,
+    enc_class_display,
+    cond_recorded_week,
+    cond_onset_date_exists,
+    encounter_ref_exists,
+    period_ref_exists
+);
+
+
+-- COUNT MedReq by week
+
+CREATE TABLE core__count_soe_medreq_week AS
+WITH discrete AS (
+    SELECT
+        core__soe_medreq.medreq_ref,
+        enc_class.display AS enc_class_display,
+        enc_class.system AS enc_class_system,
+        date_trunc(
+            'week', core__soe_medreq.medreq_recorded_date
+        ) AS medreq_recorded_week,
+        coalesce(
+            core__soe_medreq.encounter_ref IS NOT NULL, FALSE
+        ) AS encounter_ref_exists,
+        coalesce(
+            core__soe_medreq.period_ref IS NOT NULL, FALSE
+        ) AS period_ref_exists
+    FROM core__soe_medreq
+)
+
+SELECT
+    count(DISTINCT medreq_ref) AS cnt,
+    enc_class_display,
+    enc_class_system,
+    medreq_recorded_week,
+    encounter_ref_exists,
+    period_ref_exists
+FROM discrete
+GROUP BY cube(
+    enc_class_display,
+    enc_class_system,
+    medreq_recorded_week,
+    encounter_ref_exists,
+    period_ref_exists
+);
+
+
+-- COUNT Document by week
+
+CREATE TABLE core__count_soe_document_week AS
+WITH discrete AS (
+    SELECT
+        core__soe_document.doc_ref,
+        enc_class.display AS enc_class_display,
+        enc_class.system AS enc_class_system,
+        date_trunc(
+            'week', date(core__soe_document.doc_start_datetime)
+        ) AS doc_start_week,
+        coalesce(
+            core__soe_document.encounter_ref IS NOT NULL, FALSE
+        ) AS encounter_ref_exists,
+        coalesce(
+            core__soe_document.period_ref IS NOT NULL, FALSE
+        ) AS period_ref_exists
+    FROM core__soe_document
+)
+
+SELECT
+    count(DISTINCT doc_ref) AS cnt,
+    enc_class_display,
+    enc_class_system,
+    doc_start_week,
+    encounter_ref_exists,
+    period_ref_exists
+FROM discrete
+GROUP BY cube(
+    enc_class_display,
+    enc_class_system,
+    doc_start_week,
+    encounter_ref_exists,
+    period_ref_exists
+);