diff --git a/src/Nest/DSL/Aggregations/CardinalityAggregationDescriptor.cs b/src/Nest/DSL/Aggregations/CardinalityAggregationDescriptor.cs
index 6cab05a3c56..7d50cac4728 100644
--- a/src/Nest/DSL/Aggregations/CardinalityAggregationDescriptor.cs
+++ b/src/Nest/DSL/Aggregations/CardinalityAggregationDescriptor.cs
@@ -13,12 +13,12 @@ public class CardinalityAggregationDescriptor<T> : MetricAggregationBaseDescript
 		where T : class
 	{
 
-		[JsonProperty("precision_treshold")]
-		internal int? _PrecisionTreshold { get; set; }
+		[JsonProperty("precision_threshold")]
+		internal int? _PrecisionThreshold { get; set; }
 
-		public CardinalityAggregationDescriptor<T> PrecisionTreshold(int precisionTreshold)
+		public CardinalityAggregationDescriptor<T> PrecisionThreshold(int precisionThreshold)
 		{
-			this._PrecisionTreshold = precisionTreshold;
+			this._PrecisionThreshold = precisionThreshold;
 			return this;
 		}
 
diff --git a/src/Nest/DSL/Query/FunctionScoreQueryDescriptor.cs b/src/Nest/DSL/Query/FunctionScoreQueryDescriptor.cs
index 33a3c43aee6..4a52b33df12 100644
--- a/src/Nest/DSL/Query/FunctionScoreQueryDescriptor.cs
+++ b/src/Nest/DSL/Query/FunctionScoreQueryDescriptor.cs
@@ -1,339 +1,413 @@
-using System;
-using System.Collections;
-using System.Collections.Generic;
-using System.Linq;
-using System.Linq.Expressions;
-using System.Text;
-using Elasticsearch.Net;
-using Nest.Resolvers;
-using Newtonsoft.Json;
-using Newtonsoft.Json.Converters;
-
-namespace Nest
-{
-    //More info about it http://www.elasticsearch.org/guide/en/elasticsearch/reference/master/query-dsl-function-score-query.html
-    [JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-    public class FunctionScoreQueryDescriptor<T> : IQuery where T : class
-    {
-        [JsonProperty(PropertyName = "functions")]
-        internal IEnumerable<FunctionScoreFunction<T>> _Functions { get; set; }
-
-        [JsonProperty(PropertyName = "query")]
-        internal BaseQuery _Query { get; set; }
-
-        [JsonProperty(PropertyName = "score_mode")]
-        [JsonConverter(typeof(StringEnumConverter))]
-        FunctionScoreMode? _ScoreMode { get; set; }
-
-        [JsonProperty(PropertyName = "boost_mode")]
-        [JsonConverter(typeof(StringEnumConverter))]
-        FunctionBoostMode? _BoostMode { get; set; }
-
-        [JsonProperty(PropertyName = "random_score")]
-        RandomScoreFunction _RandomScore { get; set; }
-
-        [JsonProperty(PropertyName = "script_score")]
-        ScriptFilterDescriptor _ScriptScore { get; set; }
-
-        bool IQuery.IsConditionless
-        {
-            get
-            {
-                return (this._Query == null || this._Query.IsConditionless) && _RandomScore == null && _ScriptScore == null && (_Functions == null || !_Functions.Any());
-            }
-        }
-
-        public FunctionScoreQueryDescriptor<T> Query(Func<QueryDescriptor<T>, BaseQuery> querySelector)
-        {
-            querySelector.ThrowIfNull("querySelector");
-            var query = new QueryDescriptor<T>();
-            var q = querySelector(query);
-
-            this._Query = q.IsConditionless ? null : q;
-            return this;
-        }
-
-        public FunctionScoreQueryDescriptor<T> Functions(params Func<FunctionScoreFunctionsDescriptor<T>, FunctionScoreFunction<T>>[] functions)
-        {
-            var descriptor = new FunctionScoreFunctionsDescriptor<T>();
-
-            foreach (var f in functions)
-            {
-                f(descriptor);
-            }
-
-            _Functions = descriptor;
-
-            return this;
-        }
-
-        public FunctionScoreQueryDescriptor<T> ScoreMode(FunctionScoreMode mode)
-        {
-            this._ScoreMode = mode;
-            return this;
-        }
-
-        public FunctionScoreQueryDescriptor<T> BoostMode(FunctionBoostMode mode)
-        {
-            this._BoostMode = mode;
-            return this;
-        }
-
-        public FunctionScoreQueryDescriptor<T> RandomScore(int? seed=null)
-        {
-            this._RandomScore = new RandomScoreFunction();
-            if (seed.HasValue)
-            {
-                _RandomScore._Seed = seed.Value;
-            }
-            return this;
-        }
-
-        public FunctionScoreQueryDescriptor<T> ScriptScore(Action<ScriptFilterDescriptor> scriptSelector)
-        {
-            var descriptor = new ScriptFilterDescriptor();
-            if (scriptSelector != null)
-                scriptSelector(descriptor);
-
-            this._ScriptScore = descriptor;
-
-            return this;
-        }
-    }
-
-    public enum FunctionScoreMode
-    {
-        multiply,
-        sum,
-        avg,
-        first,
-        max,
-        min
-    }
-
-    public enum FunctionBoostMode
-    {
-        multiply,
-        replace,
-        sum,
-        avg,
-        max,
-        min
-    }
-
-    public class FunctionScoreFunctionsDescriptor<T> : IEnumerable<FunctionScoreFunction<T>> where T : class
-    {
-        internal List<FunctionScoreFunction<T>> _Functions { get; set; }
-
-        public FunctionScoreFunctionsDescriptor()
-        {
-            this._Functions = new List<FunctionScoreFunction<T>>();
-        }
-
-        public FunctionScoreFunction<T> Gauss(Expression<Func<T, object>> objectPath, Action<FunctionScoreDecayFieldDescriptor> db)
-        {
-            var fn = new GaussFunction<T>(objectPath, db);
-            this._Functions.Add(fn);
-            return fn;
-        }
-
-        public FunctionScoreFunction<T> Linear(Expression<Func<T, object>> objectPath, Action<FunctionScoreDecayFieldDescriptor> db)
-        {
-            var fn = new LinearFunction<T>(objectPath, db);
-            this._Functions.Add(fn);
-            return fn;
-        }
-
-        public FunctionScoreFunction<T> Exp(Expression<Func<T, object>> objectPath, Action<FunctionScoreDecayFieldDescriptor> db)
-        {
-            var fn = new ExpFunction<T>(objectPath, db);
-            this._Functions.Add(fn);
-            return fn;
-        }
-
-        public BoostFactorFunction<T> BoostFactor(double value)
-        {
-            var fn = new BoostFactorFunction<T>(value);
-            this._Functions.Add(fn);
-            return fn;
-        }
-
-        public ScriptScoreFunction<T> ScriptScore(Action<ScriptFilterDescriptor> scriptSelector)
-        {
-            var fn = new ScriptScoreFunction<T>(scriptSelector);
-            this._Functions.Add(fn);
-            return fn;
-        }
-
-        public IEnumerator<FunctionScoreFunction<T>> GetEnumerator()
-        {
-            return _Functions.GetEnumerator();
-        }
-
-        IEnumerator IEnumerable.GetEnumerator()
-        {
-            return _Functions.GetEnumerator();
-        }
-    }
-
-    [JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-    public class FunctionScoreFunction<T>
-    {
-    }
-
-    public class FunctionScoreDecayFieldDescriptor
-    {
-        [JsonProperty(PropertyName = "origin")]
-        internal string _Origin { get; set; }
-
-        [JsonProperty(PropertyName = "scale")]
-        internal string _Scale { get; set; }
-
-        [JsonProperty(PropertyName = "offset")]
-        internal string _Offset { get; set; }
-
-        [JsonProperty(PropertyName = "decay")]
-        internal double? _Decay { get; set; }
-
-        public FunctionScoreDecayFieldDescriptor Origin(string origin)
-        {
-            this._Origin = origin;
-            return this;
-        }
-
-        public FunctionScoreDecayFieldDescriptor Scale(string scale)
-        {
-            this._Scale = scale;
-            return this;
-        }
-
-        public FunctionScoreDecayFieldDescriptor Offset(string offset)
-        {
-            this._Offset = offset;
-            return this;
-        }
-
-        public FunctionScoreDecayFieldDescriptor Decay(double? decay)
-        {
-            this._Decay = decay;
-            return this;
-        }
-    }
-
-    [JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-    public class FunctionScoreDecayFunction<T> : FunctionScoreFunction<T>
-    {
-    }
-
-    [JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-    public class FunctionScoreFilteredFunction<T> : FunctionScoreFunction<T> where T : class
-    {
-        [JsonProperty(PropertyName = "filter")]
-        internal BaseFilter _Filter { get; set; }
-
-        public FunctionScoreFunction<T> Filter(Func<FilterDescriptor<T>, BaseFilter> filterSelector)
-        {
-            filterSelector.ThrowIfNull("filterSelector");
-            var filter = new FilterDescriptor<T>();
-            var f = filterSelector(filter);
-
-            this._Filter = f;
-            return this;
-        }
-    }
-
-    [JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-    public class GaussFunction<T> : FunctionScoreDecayFunction<T>
-    {
-        [JsonProperty(PropertyName = "gauss")]
-        [JsonConverter(typeof(DictionaryKeysAreNotPropertyNamesJsonConverter))]
-        internal IDictionary<PropertyPathMarker, FunctionScoreDecayFieldDescriptor> _GaussDescriptor { get; set; }
-
-        public GaussFunction(Expression<Func<T, object>> objectPath, Action<FunctionScoreDecayFieldDescriptor> descriptorBuilder)
-        {
-            _GaussDescriptor = new Dictionary<PropertyPathMarker, FunctionScoreDecayFieldDescriptor>();
-
-            var descriptor = new FunctionScoreDecayFieldDescriptor();
-            descriptorBuilder(descriptor);
-            _GaussDescriptor[objectPath] = descriptor;
-        }
-    }
-
-    [JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-    public class LinearFunction<T> : FunctionScoreDecayFunction<T>
-    {
-        [JsonProperty(PropertyName = "linear")]
-        [JsonConverter(typeof(DictionaryKeysAreNotPropertyNamesJsonConverter))]
-        internal IDictionary<PropertyPathMarker, FunctionScoreDecayFieldDescriptor> _LinearDescriptor { get; set; }
-
-        public LinearFunction(Expression<Func<T, object>> objectPath, Action<FunctionScoreDecayFieldDescriptor> descriptorBuilder)
-        {
-            _LinearDescriptor = new Dictionary<PropertyPathMarker, FunctionScoreDecayFieldDescriptor>();
-
-            var descriptor = new FunctionScoreDecayFieldDescriptor();
-            descriptorBuilder(descriptor);
-            _LinearDescriptor[objectPath] = descriptor;
-        }
-    }
-
-    [JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-    public class ExpFunction<T> : FunctionScoreDecayFunction<T>
-    {
-        [JsonProperty(PropertyName = "exp")]
-        [JsonConverter(typeof(DictionaryKeysAreNotPropertyNamesJsonConverter))]
-        internal IDictionary<PropertyPathMarker, FunctionScoreDecayFieldDescriptor> _ExpDescriptor { get; set; }
-
-        public ExpFunction(Expression<Func<T, object>> objectPath, Action<FunctionScoreDecayFieldDescriptor> descriptorBuilder)
-        {
-            _ExpDescriptor = new Dictionary<PropertyPathMarker, FunctionScoreDecayFieldDescriptor>();
-
-            var descriptor = new FunctionScoreDecayFieldDescriptor();
-            descriptorBuilder(descriptor);
-            _ExpDescriptor[objectPath] = descriptor;
-        }
-    }
-
-    [JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-    public class BoostFactorFunction<T> : FunctionScoreFilteredFunction<T> where T : class
-    {
-        [JsonProperty(PropertyName = "boost_factor")]
-        internal double _BoostFactor { get; set; }
-
-        public BoostFactorFunction(double boostFactor)
-        {
-            _BoostFactor = boostFactor;
-        }
-    }
-
-    [JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-    public class ScriptScoreFunction<T> : FunctionScoreFilteredFunction<T> where T : class
-    {
-        [JsonProperty(PropertyName = "script_score")]
-        internal ScriptFilterDescriptor _ScriptScore { get; set; }
-
-        public ScriptScoreFunction(Action<ScriptFilterDescriptor> scriptSelector)
-        {
-            var descriptor = new ScriptFilterDescriptor();
-            if (scriptSelector != null)
-                scriptSelector(descriptor);
-
-            this._ScriptScore = descriptor;
-        }
-    }
-
-    [JsonObject(MemberSerialization = MemberSerialization.OptIn)]
-    public class RandomScoreFunction
-    {
-        [JsonProperty(PropertyName = "seed")]
-        internal int? _Seed { get; set; }
-
-        public RandomScoreFunction(int seed)
-        {
-            _Seed = seed;
-        }
-
-        public RandomScoreFunction()
-        {
-        }
-    }
+using Nest.Resolvers;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Converters;
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Linq.Expressions;
+
+namespace Nest
+{
+	//More info about it http://www.elasticsearch.org/guide/en/elasticsearch/reference/master/query-dsl-function-score-query.html
+	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
+	public class FunctionScoreQueryDescriptor<T> : IQuery where T : class
+	{
+		[JsonProperty(PropertyName = "functions")]
+		internal IEnumerable<FunctionScoreFunction<T>> _Functions { get; set; }
+
+		[JsonProperty(PropertyName = "query")]
+		internal BaseQuery _Query { get; set; }
+
+		[JsonProperty(PropertyName = "score_mode")]
+		[JsonConverter(typeof (StringEnumConverter))]
+		private FunctionScoreMode? _ScoreMode { get; set; }
+
+		[JsonProperty(PropertyName = "boost_mode")]
+		[JsonConverter(typeof (StringEnumConverter))]
+		private FunctionBoostMode? _BoostMode { get; set; }
+
+		[JsonProperty(PropertyName = "random_score")]
+		private RandomScoreFunction _RandomScore { get; set; }
+
+		[JsonProperty(PropertyName = "script_score")]
+		private ScriptFilterDescriptor _ScriptScore { get; set; }
+
+		bool IQuery.IsConditionless
+		{
+			get
+			{
+				return (this._Query == null || this._Query.IsConditionless) && _RandomScore == null && _ScriptScore == null &&
+				       (_Functions == null || !_Functions.Any());
+			}
+		}
+
+		public FunctionScoreQueryDescriptor<T> Query(Func<QueryDescriptor<T>, BaseQuery> querySelector)
+		{
+			querySelector.ThrowIfNull("querySelector");
+			var query = new QueryDescriptor<T>();
+			var q = querySelector(query);
+
+			this._Query = q.IsConditionless ? null : q;
+			return this;
+		}
+
+		public FunctionScoreQueryDescriptor<T> Functions(
+			params Func<FunctionScoreFunctionsDescriptor<T>, FunctionScoreFunction<T>>[] functions)
+		{
+			var descriptor = new FunctionScoreFunctionsDescriptor<T>();
+
+			foreach (var f in functions)
+			{
+				f(descriptor);
+			}
+
+			_Functions = descriptor;
+
+			return this;
+		}
+
+		public FunctionScoreQueryDescriptor<T> ScoreMode(FunctionScoreMode mode)
+		{
+			this._ScoreMode = mode;
+			return this;
+		}
+
+		public FunctionScoreQueryDescriptor<T> BoostMode(FunctionBoostMode mode)
+		{
+			this._BoostMode = mode;
+			return this;
+		}
+
+		public FunctionScoreQueryDescriptor<T> RandomScore(int? seed = null)
+		{
+			this._RandomScore = new RandomScoreFunction();
+			if (seed.HasValue)
+			{
+				_RandomScore._Seed = seed.Value;
+			}
+			return this;
+		}
+
+		public FunctionScoreQueryDescriptor<T> ScriptScore(Action<ScriptFilterDescriptor> scriptSelector)
+		{
+			var descriptor = new ScriptFilterDescriptor();
+			if (scriptSelector != null)
+				scriptSelector(descriptor);
+
+			this._ScriptScore = descriptor;
+
+			return this;
+		}
+	}
+
+	public enum FunctionScoreMode
+	{
+		multiply,
+		sum,
+		avg,
+		first,
+		max,
+		min
+	}
+
+	public enum FunctionBoostMode
+	{
+		multiply,
+		replace,
+		sum,
+		avg,
+		max,
+		min
+	}
+
+	public class FunctionScoreFunctionsDescriptor<T> : IEnumerable<FunctionScoreFunction<T>> where T : class
+	{
+		internal List<FunctionScoreFunction<T>> _Functions { get; set; }
+
+		public FunctionScoreFunctionsDescriptor()
+		{
+			this._Functions = new List<FunctionScoreFunction<T>>();
+		}
+
+		public FunctionScoreFunction<T> Gauss(Expression<Func<T, object>> objectPath,
+			Action<FunctionScoreDecayFieldDescriptor> db)
+		{
+			var fn = new GaussFunction<T>(objectPath, db);
+			this._Functions.Add(fn);
+			return fn;
+		}
+
+		public FunctionScoreFunction<T> Linear(Expression<Func<T, object>> objectPath,
+			Action<FunctionScoreDecayFieldDescriptor> db)
+		{
+			var fn = new LinearFunction<T>(objectPath, db);
+			this._Functions.Add(fn);
+			return fn;
+		}
+
+		public FunctionScoreFunction<T> Exp(Expression<Func<T, object>> objectPath,
+			Action<FunctionScoreDecayFieldDescriptor> db)
+		{
+			var fn = new ExpFunction<T>(objectPath, db);
+			this._Functions.Add(fn);
+			return fn;
+		}
+
+		public BoostFactorFunction<T> BoostFactor(double value)
+		{
+			var fn = new BoostFactorFunction<T>(value);
+			this._Functions.Add(fn);
+			return fn;
+		}
+
+		public FieldValueFactor<T> FieldValueFactor(Action<FieldValueFactorDescriptor<T>> db)
+		{
+			var fn = new FieldValueFactor<T>(db);
+			this._Functions.Add(fn);
+			return fn;
+		}
+
+		public ScriptScoreFunction<T> ScriptScore(Action<ScriptFilterDescriptor> scriptSelector)
+		{
+			var fn = new ScriptScoreFunction<T>(scriptSelector);
+			this._Functions.Add(fn);
+			return fn;
+		}
+
+		public IEnumerator<FunctionScoreFunction<T>> GetEnumerator()
+		{
+			return _Functions.GetEnumerator();
+		}
+
+		IEnumerator IEnumerable.GetEnumerator()
+		{
+			return _Functions.GetEnumerator();
+		}
+	}
+
+	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
+	public class FunctionScoreFunction<T>
+	{
+	}
+
+	public class FieldValueFactorDescriptor<T>
+	{
+		[JsonProperty("field")]
+		internal PropertyPathMarker _Field { get; set; }
+
+		[JsonProperty("factor")]
+		internal double? _Factor { get; set; }
+
+		[JsonProperty("modifier")]
+		[JsonConverter(typeof (StringEnumConverter))]
+		internal FieldValueFactorModifier? _Modifier { get; set; }
+
+		public FieldValueFactorDescriptor<T> Field(Expression<Func<T, object>> field)
+		{
+			this._Field = field;
+			return this;
+		}
+
+		public FieldValueFactorDescriptor<T> Factor(double factor)
+		{
+			this._Factor = factor;
+			return this;
+		}
+
+		public FieldValueFactorDescriptor<T> Modifier(FieldValueFactorModifier modifier)
+		{
+			this._Modifier = modifier;
+			return this;
+		}
+	}
+
+	public class FunctionScoreDecayFieldDescriptor
+	{
+		[JsonProperty(PropertyName = "origin")]
+		internal string _Origin { get; set; }
+
+		[JsonProperty(PropertyName = "scale")]
+		internal string _Scale { get; set; }
+
+		[JsonProperty(PropertyName = "offset")]
+		internal string _Offset { get; set; }
+
+		[JsonProperty(PropertyName = "decay")]
+		internal double? _Decay { get; set; }
+
+		public FunctionScoreDecayFieldDescriptor Origin(string origin)
+		{
+			this._Origin = origin;
+			return this;
+		}
+
+		public FunctionScoreDecayFieldDescriptor Scale(string scale)
+		{
+			this._Scale = scale;
+			return this;
+		}
+
+		public FunctionScoreDecayFieldDescriptor Offset(string offset)
+		{
+			this._Offset = offset;
+			return this;
+		}
+
+		public FunctionScoreDecayFieldDescriptor Decay(double? decay)
+		{
+			this._Decay = decay;
+			return this;
+		}
+	}
+
+	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
+	public class FunctionScoreDecayFunction<T> : FunctionScoreFunction<T>
+	{
+	}
+
+	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
+	public class FunctionScoreFilteredFunction<T> : FunctionScoreFunction<T> where T : class
+	{
+		[JsonProperty(PropertyName = "filter")]
+		internal BaseFilter _Filter { get; set; }
+
+		public FunctionScoreFunction<T> Filter(Func<FilterDescriptor<T>, BaseFilter> filterSelector)
+		{
+			filterSelector.ThrowIfNull("filterSelector");
+			var filter = new FilterDescriptor<T>();
+			var f = filterSelector(filter);
+
+			this._Filter = f;
+			return this;
+		}
+	}
+
+	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
+	public class GaussFunction<T> : FunctionScoreDecayFunction<T>
+	{
+		[JsonProperty(PropertyName = "gauss")]
+		[JsonConverter(typeof (DictionaryKeysAreNotPropertyNamesJsonConverter))]
+		internal IDictionary<PropertyPathMarker, FunctionScoreDecayFieldDescriptor> _GaussDescriptor { get; set; }
+
+		public GaussFunction(Expression<Func<T, object>> objectPath,
+			Action<FunctionScoreDecayFieldDescriptor> descriptorBuilder)
+		{
+			_GaussDescriptor = new Dictionary<PropertyPathMarker, FunctionScoreDecayFieldDescriptor>();
+
+			var descriptor = new FunctionScoreDecayFieldDescriptor();
+			descriptorBuilder(descriptor);
+			_GaussDescriptor[objectPath] = descriptor;
+		}
+	}
+
+	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
+	public class LinearFunction<T> : FunctionScoreDecayFunction<T>
+	{
+		[JsonProperty(PropertyName = "linear")]
+		[JsonConverter(typeof (DictionaryKeysAreNotPropertyNamesJsonConverter))]
+		internal IDictionary<PropertyPathMarker, FunctionScoreDecayFieldDescriptor> _LinearDescriptor { get; set; }
+
+		public LinearFunction(Expression<Func<T, object>> objectPath,
+			Action<FunctionScoreDecayFieldDescriptor> descriptorBuilder)
+		{
+			_LinearDescriptor = new Dictionary<PropertyPathMarker, FunctionScoreDecayFieldDescriptor>();
+
+			var descriptor = new FunctionScoreDecayFieldDescriptor();
+			descriptorBuilder(descriptor);
+			_LinearDescriptor[objectPath] = descriptor;
+		}
+	}
+
+	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
+	public class ExpFunction<T> : FunctionScoreDecayFunction<T>
+	{
+		[JsonProperty(PropertyName = "exp")]
+		[JsonConverter(typeof (DictionaryKeysAreNotPropertyNamesJsonConverter))]
+		internal IDictionary<PropertyPathMarker, FunctionScoreDecayFieldDescriptor> _ExpDescriptor { get; set; }
+
+		public ExpFunction(Expression<Func<T, object>> objectPath, Action<FunctionScoreDecayFieldDescriptor> descriptorBuilder)
+		{
+			_ExpDescriptor = new Dictionary<PropertyPathMarker, FunctionScoreDecayFieldDescriptor>();
+
+			var descriptor = new FunctionScoreDecayFieldDescriptor();
+			descriptorBuilder(descriptor);
+			_ExpDescriptor[objectPath] = descriptor;
+		}
+	}
+
+	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
+	public class BoostFactorFunction<T> : FunctionScoreFilteredFunction<T> where T : class
+	{
+		[JsonProperty(PropertyName = "boost_factor")]
+		internal double _BoostFactor { get; set; }
+
+		public BoostFactorFunction(double boostFactor)
+		{
+			_BoostFactor = boostFactor;
+		}
+	}
+
+	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
+	public class FieldValueFactor<T> : FunctionScoreFilteredFunction<T> where T : class
+	{
+		[JsonProperty(PropertyName = "field_value_factor")]
+		internal FieldValueFactorDescriptor<T> _FieldValueFactor { get; set; }
+
+		public FieldValueFactor(Action<FieldValueFactorDescriptor<T>> descriptorBuilder)
+		{
+			var descriptor = new FieldValueFactorDescriptor<T>();
+			descriptorBuilder(descriptor);
+			if (descriptor._Field.IsConditionless())
+				throw new DslException("Field name not set for field value factor function");
+
+			this._FieldValueFactor = descriptor;
+		}
+	}
+
+	public enum FieldValueFactorModifier
+	{
+		none,
+		log,
+		log1p,
+		log2p,
+		ln,
+		ln1p,
+		ln2p,
+		square,
+		sqrt,
+		reciprocal
+	}
+
+	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
+	public class ScriptScoreFunction<T> : FunctionScoreFilteredFunction<T> where T : class
+	{
+		[JsonProperty(PropertyName = "script_score")]
+		internal ScriptFilterDescriptor _ScriptScore { get; set; }
+
+		public ScriptScoreFunction(Action<ScriptFilterDescriptor> scriptSelector)
+		{
+			var descriptor = new ScriptFilterDescriptor();
+			if (scriptSelector != null)
+				scriptSelector(descriptor);
+
+			this._ScriptScore = descriptor;
+		}
+	}
+
+	[JsonObject(MemberSerialization = MemberSerialization.OptIn)]
+	public class RandomScoreFunction
+	{
+		[JsonProperty(PropertyName = "seed")]
+		internal int? _Seed { get; set; }
+
+		public RandomScoreFunction(int seed)
+		{
+			_Seed = seed;
+		}
+
+		public RandomScoreFunction()
+		{
+		}
+	}
 }
\ No newline at end of file
diff --git a/src/Tests/Nest.Tests.Unit/Search/Query/Singles/FunctionScoreQueryJson.cs b/src/Tests/Nest.Tests.Unit/Search/Query/Singles/FunctionScoreQueryJson.cs
index 78f89a5bf70..cee9dc14d43 100644
--- a/src/Tests/Nest.Tests.Unit/Search/Query/Singles/FunctionScoreQueryJson.cs
+++ b/src/Tests/Nest.Tests.Unit/Search/Query/Singles/FunctionScoreQueryJson.cs
@@ -1,31 +1,31 @@
-using NUnit.Framework;
-using Nest.DSL.Query;
-using Nest.Tests.MockData.Domain;
-
-namespace Nest.Tests.Unit.Search.Query.Singles
-{
-	[TestFixture]
-	public class FunctionScoreQueryTests
-	{
-		[Test]
-		public void FunctionScoreQuery()
-		{
-			var s = new SearchDescriptor<ElasticsearchProject>().From(0).Size(10)
-				.Query(q => q
-					.FunctionScore(fs => fs
-						.Query(qq => qq.MatchAll())
-						.Functions(
-							f => f.Gauss(x => x.StartedOn, d => d.Scale("42w")),
-							f => f.Linear(x => x.FloatValue, d => d.Scale("0.3")),
-							f => f.Exp(x => x.DoubleValue, d => d.Scale("0.5")),
-							f => f.BoostFactor(2)
-						)
-						.ScoreMode(FunctionScoreMode.sum)
-                        .BoostMode(FunctionBoostMode.replace)
-					)
-				).Fields(x => x.Content);
-
-			var json = TestElasticClient.Serialize(s);
+using Nest.Tests.MockData.Domain;
+using NUnit.Framework;
+
+namespace Nest.Tests.Unit.Search.Query.Singles
+{
+	[TestFixture]
+	public class FunctionScoreQueryTests
+	{
+		[Test]
+		public void FunctionScoreQuery()
+		{
+			var s = new SearchDescriptor<ElasticsearchProject>().From(0).Size(10)
+				.Query(q => q
+					.FunctionScore(fs => fs
+						.Query(qq => qq.MatchAll())
+						.Functions(
+							f => f.Gauss(x => x.StartedOn, d => d.Scale("42w")),
+							f => f.Linear(x => x.FloatValue, d => d.Scale("0.3")),
+							f => f.Exp(x => x.DoubleValue, d => d.Scale("0.5")),
+							f => f.BoostFactor(2.0),
+							f => f.FieldValueFactor(op => op.Field(ff => ff.DoubleValue).Factor(2.5).Modifier(FieldValueFactorModifier.sqrt))
+						)
+						.ScoreMode(FunctionScoreMode.sum)
+						.BoostMode(FunctionBoostMode.replace)
+					)
+				).Fields(x => x.Content);
+
+			var json = TestElasticClient.Serialize(s);
 			var expected = @"{ 
                 from: 0, size: 10, 
 				query : {
@@ -34,7 +34,8 @@ public void FunctionScoreQuery()
                             {gauss:  { startedOn  : { scale: '42w'}}},
                             {linear: { floatValue : { scale: '0.3'}}},
                             {exp:    { doubleValue: { scale: '0.5'}}}, 
-                            {boost_factor: 2.0 }
+                            {boost_factor: 2.0 },
+							{field_value_factor: { field: 'doubleValue', factor: 2.5, modifier: 'sqrt'}}
                         ],				
 						query : { match_all : {} },
                         score_mode: 'sum',
@@ -42,29 +43,30 @@ public void FunctionScoreQuery()
 					}
 				},
                 fields: [""content""]
-			}";
-			Assert.True(json.JsonEquals(expected), json);
-		}
-		
-		[Test]
-		public void FunctionScoreQueryConditionless()
-		{
-			var s = new SearchDescriptor<ElasticsearchProject>().From(0).Size(10)
-				.Query(q => q
-					.FunctionScore(fs => fs
-						.Query(qq => qq.Term("", ""))
-						.Functions(
-							f => f.Gauss(x => x.StartedOn, d => d.Scale("42w")),
-							f => f.Linear(x => x.FloatValue, d => d.Scale("0.3")),
-							f => f.Exp(x => x.DoubleValue, d => d.Scale("0.5")),
-							f => f.BoostFactor(2)
-						)
-						.ScoreMode(FunctionScoreMode.sum)
-                        .BoostMode(FunctionBoostMode.replace)
-					)
-				).Fields(x => x.Content);
-
-			var json = TestElasticClient.Serialize(s);
+			}";
+			Assert.True(json.JsonEquals(expected), json);
+		}
+
+		[Test]
+		public void FunctionScoreQueryConditionless()
+		{
+			var s = new SearchDescriptor<ElasticsearchProject>().From(0).Size(10)
+				.Query(q => q
+					.FunctionScore(fs => fs
+						.Query(qq => qq.Term("", ""))
+						.Functions(
+							f => f.Gauss(x => x.StartedOn, d => d.Scale("42w")),
+							f => f.Linear(x => x.FloatValue, d => d.Scale("0.3")),
+							f => f.Exp(x => x.DoubleValue, d => d.Scale("0.5")),
+							f => f.BoostFactor(2),
+							f => f.FieldValueFactor(db => db.Field(fa => fa.DoubleValue).Factor(3.4).Modifier(FieldValueFactorModifier.ln))
+						)
+						.ScoreMode(FunctionScoreMode.sum)
+						.BoostMode(FunctionBoostMode.replace)
+					)
+				).Fields(x => x.Content);
+
+			var json = TestElasticClient.Serialize(s);
 			var expected = @"{ 
                 from: 0, size: 10, 
 				query : {
@@ -73,15 +75,29 @@ public void FunctionScoreQueryConditionless()
                             {gauss:  { startedOn  : { scale: '42w'}}},
                             {linear: { floatValue : { scale: '0.3'}}},
                             {exp:    { doubleValue: { scale: '0.5'}}}, 
-                            {boost_factor: 2.0 }
+                            {boost_factor: 2.0 },
+							{field_value_factor: { field: 'doubleValue', factor: 3.4, modifier: 'ln'}}
                         ],				
                         score_mode: 'sum',
                         boost_mode: 'replace',
 					}
 				},
                 fields: [""content""]
-			}";
-			Assert.True(json.JsonEquals(expected), json);
-		}
-	}
+			}";
+			Assert.True(json.JsonEquals(expected), json);
+		}
+
+		[Test]
+		public void ConditionlessFieldValueFactor()
+		{
+			Assert.Throws<DslException>(() => new SearchDescriptor<ElasticsearchProject>().From(0).Size(10)
+				.Query(q => q
+					.FunctionScore(fs => fs
+						.Query(qq => qq.Term("", ""))
+						.Functions(
+							f => f.FieldValueFactor(db => db.Factor(3.4).Modifier(FieldValueFactorModifier.ln))
+						))
+				));
+		}
+	}
 }
\ No newline at end of file