diff --git a/errors.go b/errors.go
index ed7fa9f..798fed0 100644
--- a/errors.go
+++ b/errors.go
@@ -12,10 +12,7 @@ import (
 // http://jsonapi.org/format/#document-top-level
 // and here: http://jsonapi.org/format/#error-objects.
 func MarshalErrors(w io.Writer, errorObjects []*ErrorObject) error {
-	if err := json.NewEncoder(w).Encode(&ErrorsPayload{Errors: errorObjects}); err != nil {
-		return err
-	}
-	return nil
+	return json.NewEncoder(w).Encode(&ErrorsPayload{Errors: errorObjects})
 }
 
 // ErrorsPayload is a serializer struct for representing a valid JSON API errors payload.
diff --git a/response.go b/response.go
index e8e85fa..3f8ab73 100644
--- a/response.go
+++ b/response.go
@@ -68,10 +68,7 @@ func MarshalPayload(w io.Writer, models interface{}) error {
 		return err
 	}
 
-	if err := json.NewEncoder(w).Encode(payload); err != nil {
-		return err
-	}
-	return nil
+	return json.NewEncoder(w).Encode(payload)
 }
 
 // Marshal does the same as MarshalPayload except it just returns the payload
@@ -128,10 +125,7 @@ func MarshalPayloadWithoutIncluded(w io.Writer, model interface{}) error {
 	}
 	payload.clearIncluded()
 
-	if err := json.NewEncoder(w).Encode(payload); err != nil {
-		return err
-	}
-	return nil
+	return json.NewEncoder(w).Encode(payload)
 }
 
 // marshalOne does the same as MarshalOnePayload except it just returns the
@@ -195,11 +189,7 @@ func MarshalOnePayloadEmbedded(w io.Writer, model interface{}) error {
 
 	payload := &OnePayload{Data: rootNode}
 
-	if err := json.NewEncoder(w).Encode(payload); err != nil {
-		return err
-	}
-
-	return nil
+	return json.NewEncoder(w).Encode(payload)
 }
 
 func visitModelNode(model interface{}, included *map[string]*Node,
@@ -280,6 +270,9 @@ func visitModelNode(model interface{}, included *map[string]*Node,
 				// We had a JSON float (numeric), but our field was not one of the
 				// allowed numeric types
 				er = ErrBadJSONAPIID
+			}
+
+			if er != nil {
 				break
 			}
 
diff --git a/runtime.go b/runtime.go
index 7dc6581..db2d9f2 100644
--- a/runtime.go
+++ b/runtime.go
@@ -8,35 +8,58 @@ import (
 	"time"
 )
 
+// Event represents a lifecycle event in the marshaling or unmarshalling
+// process.
 type Event int
 
 const (
+	// UnmarshalStart is the Event that is sent when deserialization of a payload
+	// begins.
 	UnmarshalStart Event = iota
+
+	// UnmarshalStop is the Event that is sent when deserialization of a payload
+	// ends.
 	UnmarshalStop
+
+	// MarshalStart is the Event that is sent sent when serialization of a payload
+	// begins.
 	MarshalStart
+
+	// MarshalStop is the Event that is sent sent when serialization of a payload
+	// ends.
 	MarshalStop
 )
 
+// Runtime has the same methods as jsonapi package for serialization and
+// deserialization but also has a ctx, a map[string]interface{} for storing
+// state, designed for instrumenting serialization timings.
 type Runtime struct {
 	ctx map[string]interface{}
 }
 
+// Events is the func type that provides the callback for handling event timings.
 type Events func(*Runtime, Event, string, time.Duration)
 
+// Instrumentation is a a global Events variable.  This is the handler for all
+// timing events.
 var Instrumentation Events
 
+// NewRuntime creates a Runtime for use in an application.
 func NewRuntime() *Runtime { return &Runtime{make(map[string]interface{})} }
 
+// WithValue adds custom state variables to the runtime context.
 func (r *Runtime) WithValue(key string, value interface{}) *Runtime {
 	r.ctx[key] = value
 
 	return r
 }
 
+// Value returns a state variable in the runtime context.
 func (r *Runtime) Value(key string) interface{} {
 	return r.ctx[key]
 }
 
+// Instrument is deprecated.
 func (r *Runtime) Instrument(key string) *Runtime {
 	return r.WithValue("instrument", key)
 }
@@ -45,12 +68,14 @@ func (r *Runtime) shouldInstrument() bool {
 	return Instrumentation != nil
 }
 
+// UnmarshalPayload has docs in request.go for UnmarshalPayload.
 func (r *Runtime) UnmarshalPayload(reader io.Reader, model interface{}) error {
 	return r.instrumentCall(UnmarshalStart, UnmarshalStop, func() error {
 		return UnmarshalPayload(reader, model)
 	})
 }
 
+// UnmarshalManyPayload has docs in request.go for UnmarshalManyPayload.
 func (r *Runtime) UnmarshalManyPayload(reader io.Reader, kind reflect.Type) (elems []interface{}, err error) {
 	r.instrumentCall(UnmarshalStart, UnmarshalStop, func() error {
 		elems, err = UnmarshalManyPayload(reader, kind)
@@ -60,6 +85,7 @@ func (r *Runtime) UnmarshalManyPayload(reader io.Reader, kind reflect.Type) (ele
 	return
 }
 
+// MarshalPayload has docs in response.go for MarshalPayload.
 func (r *Runtime) MarshalPayload(w io.Writer, model interface{}) error {
 	return r.instrumentCall(MarshalStart, MarshalStop, func() error {
 		return MarshalPayload(w, model)