diff --git a/crates/irtt-stats/src/lib.rs b/crates/irtt-stats/src/lib.rs
index 213c3cd..8cb471c 100644
--- a/crates/irtt-stats/src/lib.rs
+++ b/crates/irtt-stats/src/lib.rs
@@ -2,21 +2,20 @@
 
 #![forbid(unsafe_code)]
 
-use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
+use std::time::Duration;
 
-use irtt_client::{
-    ClientEvent, ClientTimestamp, OneWayDelaySample, ReceivedStatsSample, RttSample, ServerTiming,
-    SignedDuration,
-};
+use irtt_client::ClientEvent;
 
 mod ipdv;
 mod loss;
+mod normalization;
 mod rolling;
 mod time_stats;
 
 use ipdv::{IpdvSample, IpdvTracker};
 use loss::loss_stats;
 pub use loss::LossStats;
+use normalization::{normalize_event, ReplySample, StatsEvent};
 use rolling::RollingEvents;
 use time_stats::TimeMetric;
 pub use time_stats::TimeStats;
@@ -411,213 +410,6 @@ impl CoreStats {
     }
 }
 
-#[derive(Debug, Clone, PartialEq)]
-enum StatsEvent {
-    Sent {
-        at: Instant,
-        bytes: usize,
-        send_call_ns: i128,
-        timer_error_ns: i128,
-    },
-    UniqueReply {
-        at: Instant,
-        is_late: bool,
-        sample: Box<ReplySample>,
-    },
-    DuplicateReply {
-        at: Instant,
-    },
-    Loss {
-        at: Instant,
-    },
-    Warning {
-        at: Instant,
-    },
-    UntrackedLate {
-        at: Instant,
-    },
-}
-
-fn normalize_event(event: &ClientEvent) -> Option<StatsEvent> {
-    match event {
-        ClientEvent::EchoSent {
-            sent_at,
-            bytes,
-            send_call,
-            timer_error,
-            ..
-        } => Some(StatsEvent::Sent {
-            at: sent_at.mono,
-            bytes: *bytes,
-            send_call_ns: duration_ns_i128(*send_call),
-            timer_error_ns: duration_ns_i128(*timer_error),
-        }),
-        ClientEvent::EchoReply {
-            seq,
-            sent_at,
-            received_at,
-            rtt,
-            server_timing,
-            one_way,
-            received_stats,
-            bytes,
-            ..
-        } => Some(StatsEvent::UniqueReply {
-            at: received_at.mono,
-            is_late: false,
-            sample: Box::new(ReplySample::from_reply_parts(
-                *seq,
-                *sent_at,
-                *received_at,
-                *rtt,
-                *server_timing,
-                *one_way,
-                *received_stats,
-                *bytes,
-            )),
-        }),
-        ClientEvent::LateReply {
-            seq,
-            sent_at: Some(sent_at),
-            received_at,
-            rtt: Some(rtt),
-            server_timing,
-            one_way,
-            received_stats,
-            bytes,
-            ..
-        } => Some(StatsEvent::UniqueReply {
-            at: received_at.mono,
-            is_late: true,
-            sample: Box::new(ReplySample::from_reply_parts(
-                *seq,
-                *sent_at,
-                *received_at,
-                *rtt,
-                *server_timing,
-                *one_way,
-                *received_stats,
-                *bytes,
-            )),
-        }),
-        ClientEvent::LateReply { received_at, .. } => Some(StatsEvent::UntrackedLate {
-            at: received_at.mono,
-        }),
-        ClientEvent::DuplicateReply { received_at, .. } => Some(StatsEvent::DuplicateReply {
-            at: received_at.mono,
-        }),
-        ClientEvent::EchoLoss { timeout_at, .. } => Some(StatsEvent::Loss { at: *timeout_at }),
-        ClientEvent::Warning { at, .. } => Some(StatsEvent::Warning { at: at.mono }),
-        ClientEvent::SessionStarted { .. }
-        | ClientEvent::NoTestCompleted { .. }
-        | ClientEvent::SessionClosed { .. } => None,
-    }
-}
-
-impl StatsEvent {
-    fn at(&self) -> Instant {
-        match self {
-            Self::Sent { at, .. }
-            | Self::UniqueReply { at, .. }
-            | Self::DuplicateReply { at }
-            | Self::Loss { at }
-            | Self::Warning { at }
-            | Self::UntrackedLate { at } => *at,
-        }
-    }
-}
-
-#[derive(Debug, Clone, PartialEq)]
-struct ReplySample {
-    bytes: usize,
-    rtt_raw_ns: i128,
-    rtt_adjusted_ns: Option<i128>,
-    send_delay_ns: Option<i128>,
-    receive_delay_ns: Option<i128>,
-    server_processing_ns: Option<i128>,
-    received_count: Option<u32>,
-    received_window: Option<u64>,
-    ipdv: IpdvSample,
-}
-
-impl ReplySample {
-    #[allow(clippy::too_many_arguments)]
-    fn from_reply_parts(
-        seq: u32,
-        sent_at: ClientTimestamp,
-        received_at: ClientTimestamp,
-        rtt: RttSample,
-        server_timing: Option<ServerTiming>,
-        one_way: Option<OneWayDelaySample>,
-        received_stats: Option<ReceivedStatsSample>,
-        bytes: usize,
-    ) -> Self {
-        let rtt_primary_ns = signed_duration_ns(rtt.effective_signed);
-        Self {
-            bytes,
-            rtt_raw_ns: duration_ns_i128(rtt.raw),
-            rtt_adjusted_ns: rtt.adjusted_signed.map(signed_duration_ns),
-            send_delay_ns: one_way
-                .and_then(|sample| sample.client_to_server)
-                .map(duration_ns_i128),
-            receive_delay_ns: one_way
-                .and_then(|sample| sample.server_to_client)
-                .map(duration_ns_i128),
-            server_processing_ns: server_timing
-                .and_then(|timing| timing.processing)
-                .map(duration_ns_i128),
-            received_count: received_stats.and_then(|stats| stats.count),
-            received_window: received_stats.and_then(|stats| stats.window),
-            ipdv: IpdvSample {
-                seq,
-                rtt_primary_ns,
-                client_send_mono: sent_at.mono,
-                client_receive_mono: received_at.mono,
-                client_send_wall_ns: system_time_ns(sent_at.wall),
-                client_receive_wall_ns: system_time_ns(received_at.wall),
-                server_receive_mono_ns: server_timing.and_then(|timing| timing.receive_mono_ns),
-                server_send_mono_ns: server_timing.and_then(|timing| timing.send_mono_ns),
-                server_receive_wall_ns: server_timing.and_then(|timing| timing.receive_wall_ns),
-                server_send_wall_ns: server_timing.and_then(|timing| timing.send_wall_ns),
-            },
-        }
-    }
-}
-
-fn system_time_ns(time: SystemTime) -> Option<i128> {
-    if let Ok(duration) = time.duration_since(UNIX_EPOCH) {
-        return Some(duration_ns_i128(duration));
-    }
-    UNIX_EPOCH
-        .duration_since(time)
-        .ok()
-        .map(|duration| -duration_ns_i128(duration))
-}
-
-fn duration_ns_i128(duration: Duration) -> i128 {
-    i128::try_from(duration.as_nanos()).unwrap_or(i128::MAX)
-}
-
-fn signed_duration_ns(duration: SignedDuration) -> i128 {
-    duration.ns
-}
-
 fn duration_from_non_negative_i128_ns(value: i128) -> Option<Duration> {
     u64::try_from(value).ok().map(Duration::from_nanos)
 }
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-    use std::time::SystemTime;
-
-    #[test]
-    fn system_time_before_epoch_is_supported() {
-        let before = UNIX_EPOCH - Duration::from_nanos(7);
-        assert_eq!(system_time_ns(before), Some(-7));
-        let after = UNIX_EPOCH + Duration::from_nanos(7);
-        assert_eq!(system_time_ns(after), Some(7));
-        let now = SystemTime::now();
-        assert!(system_time_ns(now).is_some());
-    }
-}
diff --git a/crates/irtt-stats/src/normalization.rs b/crates/irtt-stats/src/normalization.rs
new file mode 100644
index 0000000..b75d8e3
--- /dev/null
+++ b/crates/irtt-stats/src/normalization.rs
@@ -0,0 +1,214 @@
+use std::time::{Duration, Instant, SystemTime, UNIX_EPOCH};
+
+use irtt_client::{
+    ClientEvent, ClientTimestamp, OneWayDelaySample, ReceivedStatsSample, RttSample, ServerTiming,
+    SignedDuration,
+};
+
+use crate::ipdv::IpdvSample;
+
+#[derive(Debug, Clone, PartialEq)]
+pub(crate) enum StatsEvent {
+    Sent {
+        at: Instant,
+        bytes: usize,
+        send_call_ns: i128,
+        timer_error_ns: i128,
+    },
+    UniqueReply {
+        at: Instant,
+        is_late: bool,
+        sample: Box<ReplySample>,
+    },
+    DuplicateReply {
+        at: Instant,
+    },
+    Loss {
+        at: Instant,
+    },
+    Warning {
+        at: Instant,
+    },
+    UntrackedLate {
+        at: Instant,
+    },
+}
+
+pub(crate) fn normalize_event(event: &ClientEvent) -> Option<StatsEvent> {
+    match event {
+        ClientEvent::EchoSent {
+            sent_at,
+            bytes,
+            send_call,
+            timer_error,
+            ..
+        } => Some(StatsEvent::Sent {
+            at: sent_at.mono,
+            bytes: *bytes,
+            send_call_ns: duration_ns_i128(*send_call),
+            timer_error_ns: duration_ns_i128(*timer_error),
+        }),
+        ClientEvent::EchoReply {
+            seq,
+            sent_at,
+            received_at,
+            rtt,
+            server_timing,
+            one_way,
+            received_stats,
+            bytes,
+            ..
+        } => Some(StatsEvent::UniqueReply {
+            at: received_at.mono,
+            is_late: false,
+            sample: Box::new(ReplySample::from_reply_parts(
+                *seq,
+                *sent_at,
+                *received_at,
+                *rtt,
+                *server_timing,
+                *one_way,
+                *received_stats,
+                *bytes,
+            )),
+        }),
+        ClientEvent::LateReply {
+            seq,
+            sent_at: Some(sent_at),
+            received_at,
+            rtt: Some(rtt),
+            server_timing,
+            one_way,
+            received_stats,
+            bytes,
+            ..
+        } => Some(StatsEvent::UniqueReply {
+            at: received_at.mono,
+            is_late: true,
+            sample: Box::new(ReplySample::from_reply_parts(
+                *seq,
+                *sent_at,
+                *received_at,
+                *rtt,
+                *server_timing,
+                *one_way,
+                *received_stats,
+                *bytes,
+            )),
+        }),
+        ClientEvent::LateReply { received_at, .. } => Some(StatsEvent::UntrackedLate {
+            at: received_at.mono,
+        }),
+        ClientEvent::DuplicateReply { received_at, .. } => Some(StatsEvent::DuplicateReply {
+            at: received_at.mono,
+        }),
+        ClientEvent::EchoLoss { timeout_at, .. } => Some(StatsEvent::Loss { at: *timeout_at }),
+        ClientEvent::Warning { at, .. } => Some(StatsEvent::Warning { at: at.mono }),
+        ClientEvent::SessionStarted { .. }
+        | ClientEvent::NoTestCompleted { .. }
+        | ClientEvent::SessionClosed { .. } => None,
+    }
+}
+
+impl StatsEvent {
+    pub(crate) fn at(&self) -> Instant {
+        match self {
+            Self::Sent { at, .. }
+            | Self::UniqueReply { at, .. }
+            | Self::DuplicateReply { at }
+            | Self::Loss { at }
+            | Self::Warning { at }
+            | Self::UntrackedLate { at } => *at,
+        }
+    }
+}
+
+#[derive(Debug, Clone, PartialEq)]
+pub(crate) struct ReplySample {
+    pub(crate) bytes: usize,
+    pub(crate) rtt_raw_ns: i128,
+    pub(crate) rtt_adjusted_ns: Option<i128>,
+    pub(crate) send_delay_ns: Option<i128>,
+    pub(crate) receive_delay_ns: Option<i128>,
+    pub(crate) server_processing_ns: Option<i128>,
+    pub(crate) received_count: Option<u32>,
+    pub(crate) received_window: Option<u64>,
+    pub(crate) ipdv: IpdvSample,
+}
+
+impl ReplySample {
+    #[allow(clippy::too_many_arguments)]
+    fn from_reply_parts(
+        seq: u32,
+        sent_at: ClientTimestamp,
+        received_at: ClientTimestamp,
+        rtt: RttSample,
+        server_timing: Option<ServerTiming>,
+        one_way: Option<OneWayDelaySample>,
+        received_stats: Option<ReceivedStatsSample>,
+        bytes: usize,
+    ) -> Self {
+        let rtt_primary_ns = signed_duration_ns(rtt.effective_signed);
+        Self {
+            bytes,
+            rtt_raw_ns: duration_ns_i128(rtt.raw),
+            rtt_adjusted_ns: rtt.adjusted_signed.map(signed_duration_ns),
+            send_delay_ns: one_way
+                .and_then(|sample| sample.client_to_server)
+                .map(duration_ns_i128),
+            receive_delay_ns: one_way
+                .and_then(|sample| sample.server_to_client)
+                .map(duration_ns_i128),
+            server_processing_ns: server_timing
+                .and_then(|timing| timing.processing)
+                .map(duration_ns_i128),
+            received_count: received_stats.and_then(|stats| stats.count),
+            received_window: received_stats.and_then(|stats| stats.window),
+            ipdv: IpdvSample {
+                seq,
+                rtt_primary_ns,
+                client_send_mono: sent_at.mono,
+                client_receive_mono: received_at.mono,
+                client_send_wall_ns: system_time_ns(sent_at.wall),
+                client_receive_wall_ns: system_time_ns(received_at.wall),
+                server_receive_mono_ns: server_timing.and_then(|timing| timing.receive_mono_ns),
+                server_send_mono_ns: server_timing.and_then(|timing| timing.send_mono_ns),
+                server_receive_wall_ns: server_timing.and_then(|timing| timing.receive_wall_ns),
+                server_send_wall_ns: server_timing.and_then(|timing| timing.send_wall_ns),
+            },
+        }
+    }
+}
+
+fn system_time_ns(time: SystemTime) -> Option<i128> {
+    if let Ok(duration) = time.duration_since(UNIX_EPOCH) {
+        return Some(duration_ns_i128(duration));
+    }
+    UNIX_EPOCH
+        .duration_since(time)
+        .ok()
+        .map(|duration| -duration_ns_i128(duration))
+}
+
+fn duration_ns_i128(duration: Duration) -> i128 {
+    i128::try_from(duration.as_nanos()).unwrap_or(i128::MAX)
+}
+
+fn signed_duration_ns(duration: SignedDuration) -> i128 {
+    duration.ns
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn system_time_before_epoch_is_supported() {
+        let before = UNIX_EPOCH - Duration::from_nanos(7);
+        assert_eq!(system_time_ns(before), Some(-7));
+        let after = UNIX_EPOCH + Duration::from_nanos(7);
+        assert_eq!(system_time_ns(after), Some(7));
+        let now = SystemTime::now();
+        assert!(system_time_ns(now).is_some());
+    }
+}
diff --git a/crates/irtt-stats/src/rolling.rs b/crates/irtt-stats/src/rolling.rs
index fc5e3f7..1cf0468 100644
--- a/crates/irtt-stats/src/rolling.rs
+++ b/crates/irtt-stats/src/rolling.rs
@@ -1,6 +1,6 @@
 use std::{collections::VecDeque, time::Duration};
 
-use crate::{CoreStats, SampleMode, Snapshot, StatsConfig, StatsEvent};
+use crate::{normalization::StatsEvent, CoreStats, SampleMode, Snapshot, StatsConfig};
 
 #[derive(Debug, Clone, PartialEq)]
 pub(crate) struct RollingEvents {